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MySQL 9.0.0
Source Code Documentation
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The class Item_multi_eq is used to represent conjunctions of equality predicates of the form field1 = field2, and field = const in where conditions and on join conditions. More...
#include <item_cmpfunc.h>
Classes | |
class | ConstFieldProxy |
class | FieldProxy |
Public Member Functions | |
~Item_multi_eq () override | |
Item_multi_eq (Item_field *lhs_field, Item_field *rhs_field) | |
Item_multi_eq (Item *const_item, Item_field *field) | |
Item_multi_eq (Item_multi_eq *item_multi_eq) | |
Item_multi_eq (const Item_multi_eq &)=delete | |
Item_multi_eq | operator= (const Item_multi_eq &)=delete |
Item_multi_eq (const Item_multi_eq &&)=delete | |
Item_multi_eq | operator= (const Item_multi_eq &&)=delete |
Item * | const_arg () const |
Returns the constant Item that this multi equality is equal to(if any). More... | |
void | set_const_arg (Item *const_item) |
bool | add (THD *thd, Item *const_item, Item_field *field) |
bool | add (THD *thd, Item *const_item) |
void | add (Item_field *field) |
uint | members () |
bool | contains (const Field *field) const |
Check whether a field is referred in the multiple equality. More... | |
Item_field * | get_first () |
Get the first field of multiple equality, use for semantic checking. More... | |
Item_field * | get_subst_item (const Item_field *field) |
Get item that can be substituted for the supplied item. More... | |
bool | merge (THD *thd, Item_multi_eq *item) |
Add members of another Item_multi_eq object. More... | |
bool | update_const (THD *thd) |
Check appearance of new constant items in the multiple equality object. More... | |
enum Functype | functype () const override |
longlong | val_int () override |
const char * | func_name () const override |
optimize_type | select_optimize (const THD *) override |
bool | cast_incompatible_args (uchar *) override |
Wrap incompatible arguments in CAST nodes to the expected data types. More... | |
bool | contains_only_equi_join_condition () const override |
Whether this Item is an equi-join condition. More... | |
template<typename Node_cmp_func > | |
void | sort (Node_cmp_func compare) |
Order field items in multiple equality according to a sorting criteria. More... | |
FieldProxy | get_fields () |
ConstFieldProxy | get_fields () const |
bool | resolve_type (THD *) override |
Resolve type-related information for this item, such as result field type, maximum size, precision, signedness, character set and collation. More... | |
bool | fix_fields (THD *thd, Item **ref) override |
void | update_used_tables () override |
Updates used tables, not null tables information and accumulates properties up the item tree, cf. More... | |
bool | walk (Item_processor processor, enum_walk walk, uchar *arg) override |
Traverses a tree of Items in prefix and/or postfix order. More... | |
void | print (const THD *thd, String *str, enum_query_type query_type) const override |
This method is used for to: More... | |
bool | eq_specific (const Item *item) const override |
Provide a more specific equality check for a function. More... | |
const CHARSET_INFO * | compare_collation () const override |
bool | equality_substitution_analyzer (uchar **) override |
Item * | equality_substitution_transformer (uchar *arg) override |
Transform an Item_multi_eq object after having added a table that represents a materialized semi-join. More... | |
float | get_filtering_effect (THD *thd, table_map filter_for_table, table_map read_tables, const MY_BITMAP *fields_to_ignore, double rows_in_table) override |
temporary area used for constant folding More... | |
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bool | is_bool_func () const override |
uint | decimal_precision () const override |
bool | created_by_in2exists () const override |
Whether this Item was created by the IN->EXISTS subquery transformation. More... | |
void | set_created_by_in2exists () |
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Item_int_func () | |
Item_int_func (const POS &pos) | |
Item_int_func (Item *a) | |
Item_int_func (const POS &pos, Item *a) | |
Item_int_func (Item *a, Item *b) | |
Item_int_func (const POS &pos, Item *a, Item *b) | |
Item_int_func (Item *a, Item *b, Item *c) | |
Item_int_func (const POS &pos, Item *a, Item *b, Item *c) | |
Item_int_func (Item *a, Item *b, Item *c, Item *d) | |
Item_int_func (const POS &pos, Item *a, Item *b, Item *c, Item *d) | |
Item_int_func (mem_root_deque< Item * > *list) | |
Item_int_func (const POS &pos, PT_item_list *opt_list) | |
Item_int_func (THD *thd, Item_int_func *item) | |
double | val_real () override |
String * | val_str (String *str) override |
bool | get_date (MYSQL_TIME *ltime, my_time_flags_t fuzzydate) override |
bool | get_time (MYSQL_TIME *ltime) override |
enum Item_result | result_type () const override |
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virtual uint | argument_count () const |
Item ** | arguments () const |
bool | reject_vector_args () |
uint | num_vector_args () |
bool | reject_geometry_args () |
bool | is_null_on_null () const |
enum Type | type () const override |
Item_func () | |
Item_func (const POS &pos) | |
Item_func (Item *a) | |
Item_func (const POS &pos, Item *a) | |
Item_func (Item *a, Item *b) | |
Item_func (const POS &pos, Item *a, Item *b) | |
Item_func (Item *a, Item *b, Item *c) | |
Item_func (const POS &pos, Item *a, Item *b, Item *c) | |
Item_func (Item *a, Item *b, Item *c, Item *d) | |
Item_func (const POS &pos, Item *a, Item *b, Item *c, Item *d) | |
Item_func (Item *a, Item *b, Item *c, Item *d, Item *e) | |
Item_func (const POS &pos, Item *a, Item *b, Item *c, Item *d, Item *e) | |
Item_func (Item *a, Item *b, Item *c, Item *d, Item *e, Item *f) | |
Item_func (const POS &pos, Item *a, Item *b, Item *c, Item *d, Item *e, Item *f) | |
Item_func (mem_root_deque< Item * > *list) | |
Item_func (const POS &pos, PT_item_list *opt_list) | |
Item_func (THD *thd, const Item_func *item) | |
virtual Item * | get_arg (uint i) |
Get the i'th argument of the function that this object represents. More... | |
virtual const Item * | get_arg (uint i) const |
Get the i'th argument of the function that this object represents. More... | |
virtual Item * | set_arg (THD *, uint, Item *) |
bool | do_itemize (Parse_context *pc, Item **res) override |
The core function that does the actual itemization. More... | |
bool | fix_fields (THD *, Item **ref) override |
bool | fix_func_arg (THD *, Item **arg) |
void | fix_after_pullout (Query_block *parent_query_block, Query_block *removed_query_block) override |
Fix after tables have been moved from one query_block level to the parent level, e.g by semijoin conversion. More... | |
virtual bool | resolve_type_inner (THD *) |
Resolve type of function after all arguments have had their data types resolved. More... | |
bool | propagate_type (THD *thd, const Type_properties &type) override |
Default implementation for all functions: Propagate base_item's type into all arguments. More... | |
virtual table_map | get_initial_pseudo_tables () const |
Returns the pseudo tables depended upon in order to evaluate this function expression. More... | |
table_map | used_tables () const override |
table_map | not_null_tables () const override |
Return table map of tables that can't be NULL tables (tables that are used in a context where if they would contain a NULL row generated by a LEFT or RIGHT join, the item would not be true). More... | |
void | update_used_tables () override |
Updates used tables, not null tables information and accumulates properties up the item tree, cf. More... | |
void | set_used_tables (table_map map) |
bool | eq (const Item *item) const override |
Compare this item with another item for equality. More... | |
virtual bool | have_rev_func () const |
virtual Item * | key_item () const |
bool | set_arguments (mem_root_deque< Item * > *list, bool context_free) |
Copy arguments from list to args array. More... | |
bool | split_sum_func (THD *thd, Ref_item_array ref_item_array, mem_root_deque< Item * > *fields) override |
See comments in Item_cmp_func::split_sum_func() More... | |
void | print (const THD *thd, String *str, enum_query_type query_type) const override |
This method is used for to: More... | |
void | print_op (const THD *thd, String *str, enum_query_type query_type) const |
void | print_args (const THD *thd, String *str, uint from, enum_query_type query_type) const |
virtual void | fix_num_length_and_dec () |
virtual bool | is_deprecated () const |
bool | get_arg0_date (MYSQL_TIME *ltime, my_time_flags_t fuzzy_date) |
bool | get_arg0_time (MYSQL_TIME *ltime) |
bool | is_null () override |
The method allows to determine nullness of a complex expression without fully evaluating it, instead of calling val*() then checking null_value. More... | |
void | signal_divide_by_null () |
void | signal_invalid_argument_for_log () |
Field * | tmp_table_field (TABLE *t_arg) override |
Item * | get_tmp_table_item (THD *thd) override |
If an Item is materialized in a temporary table, a different Item may have to be used in the part of the query that runs after the materialization. More... | |
my_decimal * | val_decimal (my_decimal *) override |
bool | agg_arg_charsets (DTCollation &c, Item **items, uint nitems, uint flags, int item_sep) |
bool | agg_arg_charsets_for_string_result (DTCollation &c, Item **items, uint nitems, int item_sep=1) |
bool | agg_arg_charsets_for_comparison (DTCollation &c, Item **items, uint nitems, int item_sep=1) |
Item * | replace_func_call (uchar *) override |
bool | walk (Item_processor processor, enum_walk walk, uchar *arg) override |
Traverses a tree of Items in prefix and/or postfix order. More... | |
Item * | transform (Item_transformer transformer, uchar *arg) override |
Transform an Item_func object with a transformer callback function. More... | |
Item * | compile (Item_analyzer analyzer, uchar **arg_p, Item_transformer transformer, uchar *arg_t) override |
Compile Item_func object with a processor and a transformer callback functions. More... | |
void | traverse_cond (Cond_traverser traverser, void *arg, traverse_order order) override |
bool | replace_equal_field_checker (uchar **arg) override |
Item * | replace_equal_field (uchar *arg) override |
virtual bool | allow_replacement (Item_field *const original, Item *const subst) |
Check whether a function allows replacement of a field with another item: In particular, a replacement that changes the metadata of some Item from non-nullable to nullable is not allowed. More... | |
double | check_float_overflow (double value) |
Throw an error if the input double number is not finite, i.e. More... | |
longlong | check_integer_overflow (longlong value, bool val_unsigned) |
Throw an error if the input BIGINT value represented by the (longlong value, bool unsigned flag) pair cannot be returned by the function, i.e. More... | |
int | check_decimal_overflow (int error) |
Throw an error if the error code of a DECIMAL operation is E_DEC_OVERFLOW. More... | |
bool | has_timestamp_args () |
bool | has_date_args () |
bool | has_time_args () |
bool | has_datetime_args () |
bool | check_valid_arguments_processor (uchar *) override |
Item * | gc_subst_transformer (uchar *arg) override |
Transformer function for GC substitution. More... | |
bool | resolve_type (THD *thd) override |
Resolve type-related information for this item, such as result field type, maximum size, precision, signedness, character set and collation. More... | |
virtual enum_const_item_cache | can_cache_json_arg (Item *arg) |
Whether an arg of a JSON function can be cached to avoid repetitive string->JSON conversion. More... | |
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Item_result_field ()=default | |
Item_result_field (const POS &pos) | |
Item_result_field (THD *thd, const Item_result_field *item) | |
Field * | get_tmp_table_field () override |
If this Item is being materialized into a temporary table, returns the field that is being materialized into. More... | |
void | set_result_field (Field *field) override |
bool | is_result_field () const override |
Field * | get_result_field () const override |
void | cleanup () override |
Called for every Item after use (preparation and execution). More... | |
bool | mark_field_in_map (uchar *arg) override |
Mark underlying field in read or write map of a table. More... | |
longlong | llrint_with_overflow_check (double realval) |
void | raise_numeric_overflow (const char *type_name) |
double | raise_float_overflow () |
longlong | raise_integer_overflow () |
int | raise_decimal_overflow () |
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Item (const Item &)=delete | |
void | operator= (Item &)=delete |
Item () | |
Item constructor for general use. More... | |
Item (THD *thd, const Item *item) | |
Constructor used by Item_field, Item_ref & aggregate functions. More... | |
Item (const POS &) | |
Parse-time context-independent constructor. More... | |
~Item () override=default | |
virtual bool | itemize (Parse_context *pc, Item **res) final |
The same as contextualize() but with additional parameter. More... | |
void | rename (char *new_name) |
rename item (used for views, cleanup() return original name). More... | |
void | init_make_field (Send_field *tmp_field, enum enum_field_types type) |
virtual void | notify_removal () |
Called when an item has been removed, can be used to notify external objects about the removal, e.g subquery predicates that are part of the sj_candidates container. More... | |
virtual void | make_field (Send_field *field) |
virtual Field * | make_string_field (TABLE *table) const |
Create a field to hold a string value from an item. More... | |
void | quick_fix_field () |
virtual void | set_can_use_prefix_key () |
bool | propagate_type (THD *thd, enum_field_types def=MYSQL_TYPE_VARCHAR, bool pin=false, bool inherit=false) |
Wrapper for easier calling of propagate_type(const Type_properties &). More... | |
virtual void | mark_json_as_scalar () |
For Items with data type JSON, mark that a string argument is treated as a scalar JSON value. More... | |
virtual std::optional< ContainedSubquery > | get_contained_subquery (const Query_block *outer_query_block) |
If this item represents a IN/ALL/ANY/comparison_operator subquery, return that (along with data on how it will be executed). More... | |
type_conversion_status | save_in_field_no_warnings (Field *field, bool no_conversions) |
Save the item into a field but do not emit any warnings. More... | |
type_conversion_status | save_in_field (Field *field, bool no_conversions) |
Save a temporal value in packed longlong format into a Field. More... | |
void | save_in_field_no_error_check (Field *field, bool no_conversions) |
A slightly faster value of save_in_field() that returns no error value (you will need to check thd->is_error() yourself), and does not support saving into hidden fields for functional indexes. More... | |
virtual void | save_org_in_field (Field *field) |
virtual bool | send (Protocol *protocol, String *str) |
This is only called from items that is not of type item_field. More... | |
bool | evaluate (THD *thd, String *str) |
Evaluate scalar item, possibly using the supplied buffer. More... | |
const Item * | unwrap_for_eq () const |
Unwrap an Item argument so that Item::eq() can see the "real" item, and not just the wrapper. More... | |
virtual Item_result | numeric_context_result_type () const |
Result type when an item appear in a numeric context. More... | |
Item_result | temporal_with_date_as_number_result_type () const |
Similar to result_type() but makes DATE, DATETIME, TIMESTAMP pretend to be numbers rather than strings. More... | |
virtual void | set_data_type_inherited () |
Set data type for item as inherited. More... | |
virtual void | pin_data_type () |
Pin the data type for the item. More... | |
enum_field_types | data_type () const |
Retrieve the derived data type of the Item. More... | |
virtual enum_field_types | actual_data_type () const |
Retrieve actual data type for an item. More... | |
virtual enum_field_types | default_data_type () const |
Get the default data (output) type for the specific item. More... | |
void | set_data_type (enum_field_types data_type) |
Set the data type of the current Item. More... | |
void | set_data_type_null () |
void | set_data_type_bool () |
void | set_data_type_int (enum_field_types type, bool unsigned_prop, uint32 max_width) |
Set the data type of the Item to be a specific integer type. More... | |
void | set_data_type_longlong () |
Set the data type of the Item to be longlong. More... | |
void | set_data_type_decimal (uint8 precision, uint8 scale) |
Set the data type of the Item to be decimal. More... | |
void | set_data_type_double () |
Set the data type of the Item to be double precision floating point. More... | |
void | set_data_type_float () |
Set the data type of the Item to be single precision floating point. More... | |
void | set_data_type_string (uint32 max_l) |
Set the Item to be variable length string. More... | |
void | set_data_type_string (ulonglong max_char_length_arg) |
Set the Item to be variable length string. More... | |
void | set_data_type_string (uint32 max_l, const CHARSET_INFO *cs) |
Set the Item to be variable length string. More... | |
void | set_data_type_string (uint32 max_l, const DTCollation &coll) |
Set the Item to be variable length string. More... | |
void | set_data_type_char (uint32 max_l) |
Set the Item to be fixed length string. More... | |
void | set_data_type_char (uint32 max_l, const CHARSET_INFO *cs) |
Set the Item to be fixed length string. More... | |
void | set_data_type_blob (enum_field_types type, uint32 max_l) |
Set the Item to be of BLOB type. More... | |
void | set_data_type_date () |
Set all type properties for Item of DATE type. More... | |
void | set_data_type_time (uint8 fsp) |
Set all type properties for Item of TIME type. More... | |
void | set_data_type_datetime (uint8 fsp) |
Set all properties for Item of DATETIME type. More... | |
void | set_data_type_timestamp (uint8 fsp) |
Set all properties for Item of TIMESTAMP type. More... | |
void | set_data_type_vector (uint32 max_l) |
Set the data type of the Item to be VECTOR. More... | |
void | set_data_type_geometry () |
Set the data type of the Item to be GEOMETRY. More... | |
void | set_data_type_json () |
Set the data type of the Item to be JSON. More... | |
void | set_data_type_year () |
Set the data type of the Item to be YEAR. More... | |
void | set_data_type_bit (uint32 max_bits) |
Set the data type of the Item to be bit. More... | |
void | set_data_type_from_item (const Item *item) |
Set data type properties of the item from the properties of another item. More... | |
virtual TYPELIB * | get_typelib () const |
Get the typelib information for an item of type set or enum. More... | |
virtual Item_result | cast_to_int_type () const |
bool | aggregate_type (const char *name, Item **items, uint count) |
Aggregates data types from array of items into current item. More... | |
virtual enum_monotonicity_info | get_monotonicity_info () const |
virtual longlong | val_int_endpoint (bool left_endp, bool *incl_endp) |
virtual longlong | val_date_temporal () |
Return date value of item in packed longlong format. More... | |
virtual longlong | val_time_temporal () |
Return time value of item in packed longlong format. More... | |
longlong | val_temporal_by_field_type () |
Return date or time value of item in packed longlong format, depending on item field type. More... | |
longlong | int_sort_key () |
Produces a key suitable for filesort. More... | |
longlong | val_temporal_with_round (enum_field_types type, uint8 dec) |
Get date or time value in packed longlong format. More... | |
ulonglong | val_uint () |
virtual String * | val_str_ascii (String *str) |
virtual bool | val_bool () |
virtual bool | val_json (Json_wrapper *result) |
Get a JSON value from an Item. More... | |
bool | error_json () |
Get the value to return from val_json() in case of errors. More... | |
bool | get_date_from_non_temporal (MYSQL_TIME *ltime, my_time_flags_t fuzzydate) |
Convert a non-temporal type to date. More... | |
bool | get_time_from_non_temporal (MYSQL_TIME *ltime) |
Convert a non-temporal type to time. More... | |
my_decimal * | error_decimal (my_decimal *decimal_value) |
Get the value to return from val_decimal() in case of errors. More... | |
String * | error_str () |
Get the value to return from val_str() in case of errors. More... | |
type_conversion_status | save_time_in_field (Field *field) |
type_conversion_status | save_date_in_field (Field *field) |
type_conversion_status | save_str_value_in_field (Field *field, String *result) |
virtual const char * | full_name () const |
virtual bool | basic_const_item () const |
Returns true if this is a simple constant item like an integer, not a constant expression. More... | |
bool | may_eval_const_item (const THD *thd) const |
virtual Item * | clone_item () const |
virtual cond_result | eq_cmp_result () const |
uint | float_length (uint decimals_par) const |
int | decimal_int_part () const |
virtual uint | time_precision () |
TIME precision of the item: 0..6. More... | |
virtual uint | datetime_precision () |
DATETIME precision of the item: 0..6. More... | |
bool | const_item () const |
Returns true if item is constant, regardless of query evaluation state. More... | |
bool | const_for_execution () const |
Returns true if item is constant during one query execution. More... | |
bool | may_evaluate_const (const THD *thd) const |
Return true if this is a const item that may be evaluated in the current phase of statement processing. More... | |
bool | is_non_deterministic () const |
bool | is_outer_reference () const |
void | print_item_w_name (const THD *thd, String *, enum_query_type query_type) const |
void | print_for_order (const THD *thd, String *str, enum_query_type query_type, const char *used_alias) const |
Prints the item when it's part of ORDER BY and GROUP BY. More... | |
bool | split_sum_func2 (THD *thd, Ref_item_array ref_item_array, mem_root_deque< Item * > *fields, Item **ref, bool skip_registered) |
virtual bool | get_timeval (my_timeval *tm, int *warnings) |
Get timestamp in "struct timeval" format. More... | |
bool | update_null_value () |
Make sure the null_value member has a correct value. More... | |
virtual void | apply_is_true () |
Apply the IS TRUE truth property, meaning that an UNKNOWN result and a FALSE result are treated the same. More... | |
virtual void | no_rows_in_result () |
virtual Item * | copy_or_same (THD *) |
virtual Item * | copy_andor_structure (THD *) |
virtual Item * | real_item () |
virtual const Item * | real_item () const |
virtual const CHARSET_INFO * | charset_for_protocol () |
template<class T > | |
auto | walk_helper_thunk (uchar *arg) |
template<class T > | |
auto | analyze_helper_thunk (uchar **arg) |
See CompileItem. More... | |
virtual bool | intro_version (uchar *) |
bool | cleanup_processor (uchar *) |
cleanup() item if it is resolved ('fixed'). More... | |
virtual bool | collect_item_field_processor (uchar *) |
virtual bool | collect_item_field_or_ref_processor (uchar *) |
virtual bool | collect_item_field_or_view_ref_processor (uchar *) |
Collects fields and view references that have the qualifying table in the specified query block. More... | |
virtual bool | add_field_to_set_processor (uchar *) |
Item::walk function. More... | |
virtual bool | visitor_processor (uchar *arg) |
A processor to handle the select lex visitor framework. More... | |
virtual bool | add_field_to_cond_set_processor (uchar *) |
Item::walk function. More... | |
virtual bool | remove_column_from_bitmap (uchar *arg) |
Visitor interface for removing all column expressions (Item_field) in this expression tree from a bitmap. More... | |
virtual bool | find_item_in_field_list_processor (uchar *) |
virtual bool | change_context_processor (uchar *) |
virtual bool | find_item_processor (uchar *arg) |
virtual bool | find_field_processor (uchar *) |
Is this an Item_field which references the given Field argument? More... | |
virtual bool | reset_wf_state (uchar *arg) |
Reset execution state for such window function types as determined by arg. More... | |
virtual bool | used_tables_for_level (uchar *arg) |
Return used table information for the specified query block (level). More... | |
virtual bool | check_column_privileges (uchar *thd) |
Check privileges. More... | |
virtual bool | inform_item_in_cond_of_tab (uchar *) |
virtual void | bind_fields () |
Bind objects from the current execution context to field objects in item trees. More... | |
virtual bool | clean_up_after_removal (uchar *arg) |
Clean up after removing the item from the item tree. More... | |
virtual bool | aggregate_check_distinct (uchar *) |
virtual bool | aggregate_check_group (uchar *) |
virtual bool | is_strong_side_column_not_in_fd (uchar *) |
virtual bool | is_column_not_in_fd (uchar *) |
virtual Bool3 | local_column (const Query_block *) const |
virtual bool | collect_scalar_subqueries (uchar *) |
virtual bool | collect_grouped_aggregates (uchar *) |
virtual bool | collect_subqueries (uchar *) |
virtual bool | update_depended_from (uchar *) |
virtual bool | has_aggregate_ref_in_group_by (uchar *) |
Check if an aggregate is referenced from within the GROUP BY clause of the query block in which it is aggregated. More... | |
bool | visit_all_analyzer (uchar **) |
virtual bool | cache_const_expr_analyzer (uchar **cache_item) |
Check if an item is a constant one and can be cached. More... | |
Item * | cache_const_expr_transformer (uchar *item) |
Cache item if needed. More... | |
virtual bool | check_partition_func_processor (uchar *) |
Check if a partition function is allowed. More... | |
virtual bool | subst_argument_checker (uchar **arg) |
virtual bool | explain_subquery_checker (uchar **) |
virtual Item * | explain_subquery_propagator (uchar *) |
virtual Item * | equal_fields_propagator (uchar *) |
virtual bool | disable_constant_propagation (uchar *) |
virtual bool | check_gcol_depend_default_processor (uchar *args) |
Check if a generated expression depends on DEFAULT function with specific column name as argument. More... | |
virtual Item * | replace_with_derived_expr (uchar *arg) |
Assuming this expression is part of a condition that would be pushed to the WHERE clause of a materialized derived table, replace, in this expression, each derived table's column with a clone of the expression lying under it in the derived table's definition. More... | |
virtual Item * | replace_with_derived_expr_ref (uchar *arg) |
Assuming this expression is part of a condition that would be pushed to the HAVING clause of a materialized derived table, replace, in this expression, each derived table's column with a reference to the expression lying under it in the derived table's definition. More... | |
virtual Item * | replace_view_refs_with_clone (uchar *arg) |
Assuming this expression is part of a condition that would be pushed to a materialized derived table, replace, in this expression, each view reference with a clone of the expression in merged derived table's definition. More... | |
virtual Item * | this_item () |
virtual const Item * | this_item () const |
virtual Item ** | this_item_addr (THD *, Item **addr_arg) |
virtual uint | cols () const |
virtual Item * | element_index (uint) |
virtual Item ** | addr (uint) |
virtual bool | check_cols (uint c) |
virtual bool | null_inside () |
virtual void | bring_value () |
Field * | tmp_table_field_from_field_type (TABLE *table, bool fixed_length) const |
Create a field based on field_type of argument. More... | |
virtual Item_field * | field_for_view_update () |
virtual Item * | truth_transformer (THD *thd, Bool_test test) |
Informs an item that it is wrapped in a truth test, in case it wants to transforms itself to implement this test by itself. More... | |
virtual Item * | update_value_transformer (uchar *) |
virtual Item * | replace_scalar_subquery (uchar *) |
When walking the item tree seeing an Item_singlerow_subselect matching a target, replace it with a substitute field used when transforming scalar subqueries into derived tables. More... | |
virtual Item * | replace_item_field (uchar *) |
Transform processor used by Query_block::transform_grouped_to_derived to replace fields which used to be at the transformed query block with corresponding fields in the new derived table containing the grouping operation of the original transformed query block. More... | |
virtual Item * | replace_item_view_ref (uchar *) |
virtual Item * | replace_aggregate (uchar *) |
virtual Item * | replace_outer_ref (uchar *) |
virtual bool | update_aggr_refs (uchar *) |
A walker processor overridden by Item_aggregate_ref, q.v. More... | |
virtual Item * | safe_charset_converter (THD *thd, const CHARSET_INFO *tocs) |
void | delete_self () |
Delete this item. More... | |
virtual bool | is_splocal () const |
virtual Settable_routine_parameter * | get_settable_routine_parameter () |
bool | is_temporal_with_date () const |
bool | is_temporal_with_date_and_time () const |
bool | is_temporal_with_time () const |
bool | is_temporal () const |
bool | has_compatible_context (Item *item) const |
Check whether this and the given item has compatible comparison context. More... | |
virtual Field::geometry_type | get_geometry_type () const |
String * | check_well_formed_result (String *str, bool send_error, bool truncate) |
Verifies that the input string is well-formed according to its character set. More... | |
bool | eq_by_collation (Item *item, const CHARSET_INFO *cs) |
Compare two items using a given collation. More... | |
CostOfItem | cost () const |
uint32 | max_char_length () const |
uint32 | max_char_length (const CHARSET_INFO *cs) const |
void | fix_char_length (uint32 max_char_length_arg) |
virtual bool | is_outer_field () const |
bool | is_blob_field () const |
Check if an item either is a blob field, or will be represented as a BLOB field if a field is created based on this item. More... | |
uint | reference_count () const |
void | increment_ref_count () |
Increment reference count. More... | |
uint | decrement_ref_count () |
Decrement reference count. More... | |
bool | has_subquery () const |
bool | has_stored_program () const |
bool | has_aggregation () const |
void | set_aggregation () |
Set the "has aggregation" property. More... | |
void | reset_aggregation () |
Reset the "has aggregation" property. More... | |
bool | has_wf () const |
void | set_wf () |
Set the "has window function" property. More... | |
bool | has_grouping_set_dep () const |
void | set_group_by_modifier () |
Set the property: this item (tree) contains a reference to a GROUP BY modifier (such as ROLLUP) More... | |
bool | has_grouping_func () const |
void | set_grouping_func () |
Set the property: this item is a call to GROUPING. More... | |
void | mark_subqueries_optimized_away () |
virtual bool | gc_subst_analyzer (uchar **) |
Analyzer function for GC substitution. More... | |
virtual bool | replace_field_processor (uchar *) |
A processor that replaces any Fields with a Create_field_wrapper. More... | |
bool | can_be_substituted_for_gc (bool array=false) const |
Check if this item is of a type that is eligible for GC substitution. More... | |
void | aggregate_float_properties (enum_field_types type, Item **items, uint nitems) |
Set max_length and decimals of function if function is floating point and result length/precision depends on argument ones. More... | |
void | aggregate_decimal_properties (Item **items, uint nitems) |
Set data type, precision and scale of item of type decimal from list of items. More... | |
uint32 | aggregate_char_width (Item **items, uint nitems) |
Calculate the maximum number of characters required by any of the items. More... | |
void | aggregate_temporal_properties (enum_field_types type, Item **items, uint nitems) |
Set data type and fractional seconds precision for temporal functions. More... | |
bool | aggregate_string_properties (enum_field_types type, const char *name, Item **items, uint nitems) |
Aggregate string properties (character set, collation and maximum length) for string function. More... | |
void | aggregate_bit_properties (Item **items, uint nitems) |
Set data type and properties of a BIT column. More... | |
virtual bool | repoint_const_outer_ref (uchar *arg) |
This function applies only to Item_field objects referred to by an Item_ref object that has been marked as a const_item. More... | |
virtual bool | strip_db_table_name_processor (uchar *) |
virtual void | compute_cost (CostOfItem *root_cost) const |
Compute the cost of evaluating this Item. More... | |
bool | is_abandoned () const |
bool | is_nullable () const |
void | set_nullable (bool nullable) |
virtual bool | supports_partial_update (const Field_json *field) const |
Check if this expression can be used for partial update of a given JSON column. More... | |
virtual bool | returns_array () const |
Whether the item returns array of its data type. More... | |
virtual void | allow_array_cast () |
A helper function to ensure proper usage of CAST(. More... | |
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virtual | ~Parse_tree_node_tmpl ()=default |
bool | is_contextualized () const |
virtual bool | contextualize (Context *pc) final |
void | error (Context *pc, const POS &pos) const |
syntax_error() function replacement for deferred reporting of syntax errors More... | |
void | error (Context *pc, const POS &pos, const char *msg) const |
syntax_error() function replacement for deferred reporting of syntax errors More... | |
void | errorf (Context *pc, const POS &pos, const char *format,...) const |
syntax_error() function replacement for deferred reporting of syntax errors More... | |
Public Attributes | |
Item * | m_const_folding [2] {nullptr, nullptr} |
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uint | arg_count |
How many arguments in 'args'. More... | |
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Item * | next_free |
Intrusive list pointer for free list. More... | |
DTCollation | collation |
Character set and collation properties assigned for this Item. More... | |
Item_name_string | item_name |
Name from query. More... | |
Item_name_string | orig_name |
Original item name (if it was renamed) More... | |
uint32 | max_length |
Maximum length of result of evaluating this item, in number of bytes. More... | |
item_marker | marker |
This member has several successive meanings, depending on the phase we're in (. More... | |
Item_result | cmp_context |
Comparison context. More... | |
bool | fixed |
True if item has been resolved. More... | |
uint8 | decimals |
Number of decimals in result when evaluating this item. More... | |
bool | null_value |
True if item is null. More... | |
bool | unsigned_flag |
bool | m_is_window_function |
True if item represents window func. More... | |
bool | hidden {false} |
If the item is in a SELECT list (Query_block::fields) and hidden is true, the item wasn't actually in the list as given by the user (it was added by the optimizer, to e.g. More... | |
bool | m_in_check_constraint_exec_ctx {false} |
True if item is a top most element in the expression being evaluated for a check constraint. More... | |
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POS | m_pos |
Private Member Functions | |
bool | compare_const (THD *thd, Item *const_item) |
Checks if the current constant value m_const_arg (that each field in fields needs to be equal to during execution) is the same as the provided constant item. More... | |
void | check_covering_prefix_keys () |
Private Attributes | |
List< Item_field > | fields |
List of equal field items. More... | |
Item * | m_const_arg {nullptr} |
Optional constant item equal to all the field items. More... | |
cmp_item * | eval_item {nullptr} |
Helper for comparing the fields. More... | |
Arg_comparator | cmp |
Helper for comparing constants. More... | |
bool | m_always_false {false} |
Flag set to true if the equality is known to be always false. More... | |
bool | compare_as_dates {false} |
Should constants be compared as datetimes? More... | |
Additional Inherited Members | |
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enum | Functype { UNKNOWN_FUNC , EQ_FUNC , EQUAL_FUNC , NE_FUNC , LT_FUNC , LE_FUNC , GE_FUNC , GT_FUNC , FT_FUNC , MATCH_FUNC , LIKE_FUNC , ISNULL_FUNC , ISNOTNULL_FUNC , ISTRUTH_FUNC , COND_AND_FUNC , COND_OR_FUNC , XOR_FUNC , BETWEEN , IN_FUNC , MULTI_EQ_FUNC , INTERVAL_FUNC , ISNOTNULLTEST_FUNC , SP_EQUALS_FUNC , SP_DISJOINT_FUNC , SP_DISTANCE_FUNC , SP_INTERSECTS_FUNC , SP_TOUCHES_FUNC , SP_CROSSES_FUNC , SP_WITHIN_FUNC , SP_CONTAINS_FUNC , SP_COVEREDBY_FUNC , SP_COVERS_FUNC , SP_OVERLAPS_FUNC , SP_STARTPOINT , SP_ENDPOINT , SP_EXTERIORRING , SP_POINTN , SP_GEOMETRYN , SP_INTERIORRINGN , NOT_FUNC , NOT_ALL_FUNC , NOW_FUNC , FROM_DAYS_FUNC , TRIG_COND_FUNC , SUSERVAR_FUNC , GUSERVAR_FUNC , COLLATE_FUNC , EXTRACT_FUNC , TYPECAST_FUNC , FUNC_SP , UDF_FUNC , NEG_FUNC , GSYSVAR_FUNC , GROUPING_FUNC , ROLLUP_GROUP_ITEM_FUNC , TABLE_FUNC , DD_INTERNAL_FUNC , PLUS_FUNC , MINUS_FUNC , MUL_FUNC , DIV_FUNC , CEILING_FUNC , ROUND_FUNC , TRUNCATE_FUNC , SQRT_FUNC , ABS_FUNC , POW_FUNC , SIGN_FUNC , FLOOR_FUNC , LOG_FUNC , LN_FUNC , LOG10_FUNC , SIN_FUNC , TAN_FUNC , COS_FUNC , COT_FUNC , DEGREES_FUNC , RADIANS_FUNC , EXP_FUNC , ASIN_FUNC , ATAN_FUNC , ACOS_FUNC , MOD_FUNC , IF_FUNC , NULLIF_FUNC , CASE_FUNC , YEAR_FUNC , YEARWEEK_FUNC , MAKEDATE_FUNC , MAKETIME_FUNC , MONTH_FUNC , MONTHNAME_FUNC , DAY_FUNC , DAYNAME_FUNC , TO_DAYS_FUNC , TO_SECONDS_FUNC , DATE_FUNC , HOUR_FUNC , MINUTE_FUNC , SECOND_FUNC , MICROSECOND_FUNC , DAYOFYEAR_FUNC , ADDTIME_FUNC , QUARTER_FUNC , WEEK_FUNC , WEEKDAY_FUNC , DATEADD_FUNC , FROM_UNIXTIME_FUNC , CONVERT_TZ_FUNC , LAST_DAY_FUNC , UNIX_TIMESTAMP_FUNC , TIME_TO_SEC_FUNC , TIMESTAMPDIFF_FUNC , DATETIME_LITERAL , GREATEST_FUNC , COALESCE_FUNC , LEAST_FUNC , JSON_CONTAINS , JSON_OVERLAPS , JSON_UNQUOTE_FUNC , MEMBER_OF_FUNC , STRCMP_FUNC , TRUE_FUNC , FALSE_FUNC , SYSDATE_FUNC , TIMEDIFF_FUNC , PERIODADD_FUNC , PERIODDIFF_FUNC , SEC_TO_TIME_FUNC , GET_FORMAT_FUNC , ANY_VALUE_FUNC , JSON_LENGTH_FUNC , JSON_DEPTH_FUNC , JSON_EXTRACT_FUNC , JSON_OBJECT_FUNC , JSON_ARRAY_FUNC , JSON_VALID_FUNC , JSON_TYPE_FUNC , JSON_PRETTY_FUNC , JSON_QUOTE_FUNC , JSON_CONTAINS_PATH_FUNC , JSON_STORAGE_SIZE_FUNC , JSON_STORAGE_FREE_FUNC , JSON_VALUE_FUNC , JSON_SEARCH_FUNC } |
enum | optimize_type { OPTIMIZE_NONE , OPTIMIZE_KEY , OPTIMIZE_OP , OPTIMIZE_NULL , OPTIMIZE_EQUAL } |
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enum | Type { INVALID_ITEM , FIELD_ITEM , FUNC_ITEM , SUM_FUNC_ITEM , AGGR_FIELD_ITEM , STRING_ITEM , INT_ITEM , DECIMAL_ITEM , REAL_ITEM , NULL_ITEM , HEX_BIN_ITEM , DEFAULT_VALUE_ITEM , COND_ITEM , REF_ITEM , INSERT_VALUE_ITEM , SUBQUERY_ITEM , ROW_ITEM , CACHE_ITEM , TYPE_HOLDER_ITEM , PARAM_ITEM , ROUTINE_FIELD_ITEM , TRIGGER_FIELD_ITEM , XPATH_NODESET_ITEM , VALUES_COLUMN_ITEM , NAME_CONST_ITEM } |
enum | cond_result { COND_UNDEF , COND_OK , COND_TRUE , COND_FALSE } |
enum | traverse_order { POSTFIX , PREFIX } |
enum | enum_const_item_cache { CACHE_NONE = 0 , CACHE_JSON_VALUE , CACHE_JSON_ATOM } |
How to cache constant JSON data. More... | |
enum | Bool_test { BOOL_IS_TRUE = 0x00 , BOOL_IS_FALSE = 0x01 , BOOL_IS_UNKNOWN = 0x02 , BOOL_NOT_TRUE = 0x03 , BOOL_NOT_FALSE = 0x04 , BOOL_NOT_UNKNOWN = 0x05 , BOOL_IDENTITY = 0x06 , BOOL_NEGATED = 0x07 , BOOL_ALWAYS_TRUE = 0x08 , BOOL_ALWAYS_FALSE = 0x09 } |
< Modifier for result transformation More... | |
enum | item_marker { MARKER_NONE = 0 , MARKER_IMPLICIT_NE_ZERO = 1 , MARKER_CONST_PROPAG = 2 , MARKER_BIT = 4 , MARKER_FUNC_DEP_NOT_NULL = 5 , MARKER_DISTINCT_GROUP = 6 , MARKER_COND_DERIVED_TABLE = 7 , MARKER_TRAVERSAL = 8 , MARKER_ICP_COND_USES_INDEX_ONLY = 10 } |
< Values for member 'marker' More... | |
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typedef Context | context_t |
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static void * | operator new (size_t size) noexcept |
static void * | operator new (size_t size, MEM_ROOT *mem_root, const std::nothrow_t &arg=std::nothrow) noexcept |
static void | operator delete (void *ptr, size_t size) |
static void | operator delete (void *, MEM_ROOT *, const std::nothrow_t &) noexcept |
static enum_field_types | result_to_type (Item_result result) |
static Item_result | type_to_result (enum_field_types type) |
static enum_field_types | type_for_variable (enum_field_types src_type) |
Provide data type for a user or system variable, based on the type of the item that is assigned to the variable. More... | |
static enum_field_types | string_field_type (uint32 max_bytes) |
Determine correct string field type, based on string length. More... | |
static const CHARSET_INFO * | default_charset () |
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static void * | operator new (size_t size, MEM_ROOT *mem_root, const std::nothrow_t &arg=std::nothrow) noexcept |
static void | operator delete (void *ptr, size_t size) |
static void | operator delete (void *, MEM_ROOT *, const std::nothrow_t &) noexcept |
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static const char * | bool_transform_names [10] |
static const Bool_test | bool_transform [10][8] |
Array that transforms a boolean test according to another. More... | |
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Item_bool_func () | |
Item_bool_func (const POS &pos) | |
Item_bool_func (Item *a) | |
Item_bool_func (const POS &pos, Item *a) | |
Item_bool_func (Item *a, Item *b, Item *c) | |
Item_bool_func (Item *a, Item *b) | |
Item_bool_func (const POS &pos, Item *a, Item *b) | |
Item_bool_func (const POS &pos, Item *a, Item *b, Item *c) | |
Item_bool_func (THD *thd, Item_bool_func *item) | |
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bool | param_type_uses_non_param (THD *thd, enum_field_types def=MYSQL_TYPE_VARCHAR) |
bool | param_type_is_default (THD *thd, uint start, uint end, uint step, enum_field_types def) |
For arguments of this Item_func ("args" array), in range [start, start+step, start+2*step,...,end[ : if they're a PS parameter with invalid (not known) type, give them default type "def". More... | |
bool | param_type_is_default (THD *thd, uint start, uint end, enum_field_types def=MYSQL_TYPE_VARCHAR) |
bool | param_type_is_rejected (uint start, uint end) |
For arguments of this Item_func ("args" array), in range [start,end[ : sends error if they're a dynamic parameter. More... | |
const Item_field * | contributes_to_filter (THD *thd, table_map read_tables, table_map filter_for_table, const MY_BITMAP *fields_to_ignore) const |
Whether or not an item should contribute to the filtering effect (. More... | |
virtual bool | may_have_named_parameters () const |
Named parameters are allowed in a parameter list. More... | |
bool | is_non_const_over_literals (uchar *) override |
bool | check_function_as_value_generator (uchar *checker_args) override |
Check if this item is allowed for a virtual column or inside a default expression. More... | |
bool | is_valid_for_pushdown (uchar *arg) override |
Check if all the columns present in this expression are from the derived table. More... | |
bool | check_column_in_window_functions (uchar *arg) override |
Check if all the columns present in this expression are present in PARTITION clause of window functions of the derived table. More... | |
bool | check_column_in_group_by (uchar *arg) override |
Check if all the columns present in this expression are present in GROUP BY clause of the derived table. More... | |
longlong | val_int_from_real () |
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String * | make_empty_result () |
Sets the result value of the function an empty string, using the current character set. More... | |
bool | skip_itemize (Item **res) |
Helper function to skip itemize() for grammar-allocated items. More... | |
virtual type_conversion_status | save_in_field_inner (Field *field, bool no_conversions) |
Helper function which does all of the work for save_in_field(Field*, bool), except some error checking common to all subclasses, which is performed by save_in_field() itself. More... | |
String * | val_string_from_real (String *str) |
String * | val_string_from_int (String *str) |
String * | val_string_from_decimal (String *str) |
String * | val_string_from_date (String *str) |
String * | val_string_from_datetime (String *str) |
String * | val_string_from_time (String *str) |
my_decimal * | val_decimal_from_real (my_decimal *decimal_value) |
my_decimal * | val_decimal_from_int (my_decimal *decimal_value) |
my_decimal * | val_decimal_from_string (my_decimal *decimal_value) |
my_decimal * | val_decimal_from_date (my_decimal *decimal_value) |
my_decimal * | val_decimal_from_time (my_decimal *decimal_value) |
longlong | val_int_from_decimal () |
longlong | val_int_from_date () |
longlong | val_int_from_time () |
longlong | val_int_from_datetime () |
longlong | val_int_from_string () |
double | val_real_from_decimal () |
double | val_real_from_string () |
bool | error_bool () |
Get the value to return from val_bool() in case of errors. More... | |
int | error_int () |
Get the value to return from val_int() in case of errors. More... | |
double | error_real () |
Get the value to return from val_real() in case of errors. More... | |
bool | error_date () |
Get the value to return from get_date() in case of errors. More... | |
bool | error_time () |
Get the value to return from get_time() in case of errors. More... | |
String * | null_return_str () |
Gets the value to return from val_str() when returning a NULL value. More... | |
bool | get_date_from_string (MYSQL_TIME *ltime, my_time_flags_t flags) |
Convert val_str() to date in MYSQL_TIME. More... | |
bool | get_date_from_real (MYSQL_TIME *ltime, my_time_flags_t flags) |
Convert val_real() to date in MYSQL_TIME. More... | |
bool | get_date_from_decimal (MYSQL_TIME *ltime, my_time_flags_t flags) |
Convert val_decimal() to date in MYSQL_TIME. More... | |
bool | get_date_from_int (MYSQL_TIME *ltime, my_time_flags_t flags) |
Convert val_int() to date in MYSQL_TIME. More... | |
bool | get_date_from_time (MYSQL_TIME *ltime) |
Convert get_time() from time to date in MYSQL_TIME. More... | |
bool | get_date_from_numeric (MYSQL_TIME *ltime, my_time_flags_t fuzzydate) |
Convert a numeric type to date. More... | |
bool | get_time_from_string (MYSQL_TIME *ltime) |
Convert val_str() to time in MYSQL_TIME. More... | |
bool | get_time_from_real (MYSQL_TIME *ltime) |
Convert val_real() to time in MYSQL_TIME. More... | |
bool | get_time_from_decimal (MYSQL_TIME *ltime) |
Convert val_decimal() to time in MYSQL_TIME. More... | |
bool | get_time_from_int (MYSQL_TIME *ltime) |
Convert val_int() to time in MYSQL_TIME. More... | |
bool | get_time_from_date (MYSQL_TIME *ltime) |
Convert date to time. More... | |
bool | get_time_from_datetime (MYSQL_TIME *ltime) |
Convert datetime to time. More... | |
bool | get_time_from_numeric (MYSQL_TIME *ltime) |
Convert a numeric type to time. More... | |
virtual longlong | val_date_temporal_at_utc () |
virtual longlong | val_time_temporal_at_utc () |
void | set_accum_properties (const Item *item) |
Set accumulated properties for an Item. More... | |
void | add_accum_properties (const Item *item) |
Add more accumulated properties to an Item. More... | |
void | set_subquery () |
Set the "has subquery" property. More... | |
void | set_stored_program () |
Set the "has stored program" property. More... | |
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Parse_tree_node_tmpl ()=delete | |
Parse_tree_node_tmpl (const POS &pos) | |
Parse_tree_node_tmpl (const POS &start_pos, const POS &end_pos) | |
bool | begin_parse_tree (Show_parse_tree *tree) |
bool | end_parse_tree (Show_parse_tree *tree) |
virtual bool | do_contextualize (Context *pc) |
Do all context-sensitive things and mark the node as contextualized. More... | |
virtual void | add_json_info (Json_object *json_obj) |
Add all the node-specific json fields. More... | |
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static bool | bit_func_returns_binary (const Item *a, const Item *b) |
static bool | mark_field_in_map (Mark_field *mark_field, Field *field) |
Helper function for mark_field_in_map(uchar *arg). More... | |
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Item ** | args |
Array of pointers to arguments. More... | |
bool | null_on_null {true} |
Affects how to determine that NULL argument implies a NULL function return. More... | |
uint | allowed_arg_cols {1} |
table_map | used_tables_cache {0} |
Value used in calculation of result of used_tables() More... | |
table_map | not_null_tables_cache {0} |
Value used in calculation of result of not_null_tables() More... | |
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Field * | result_field {nullptr} |
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String | str_value |
str_values's main purpose is to cache the value in save_in_field More... | |
uint8 | m_accum_properties |
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static constexpr uint8 | PROP_SUBQUERY = 0x01 |
Set of properties that are calculated by accumulation from underlying items. More... | |
static constexpr uint8 | PROP_STORED_PROGRAM = 0x02 |
static constexpr uint8 | PROP_AGGREGATION = 0x04 |
static constexpr uint8 | PROP_WINDOW_FUNCTION = 0x08 |
static constexpr uint8 | PROP_HAS_GROUPING_SET_DEP = 0x10 |
Set if the item or one or more of the underlying items contains a GROUP BY modifier (such as ROLLUP). More... | |
static constexpr uint8 | PROP_GROUPING_FUNC = 0x20 |
Set if the item or one or more of the underlying items is a GROUPING function. More... | |
The class Item_multi_eq is used to represent conjunctions of equality predicates of the form field1 = field2, and field = const in where conditions and on join conditions.
All equality predicates of the form field1=field2 contained in a conjunction are substituted for a sequence of items of this class. An item of this class Item_multi_eq(f1,f2,...fk) represents a multiple equality f1=f2=...=fk.
If a conjunction contains predicates f1=f2 and f2=f3, a new item of this class is created Item_multi_eq(f1,f2,f3) representing the multiple equality f1=f2=f3 that substitutes the above equality predicates in the conjunction. A conjunction of the predicates f2=f1 and f3=f1 and f3=f2 will be substituted for the item representing the same multiple equality f1=f2=f3. An item Item_multi_eq(f1,f2) can appear instead of a conjunction of f2=f1 and f1=f2, or instead of just the predicate f1=f2.
An item of the class Item_multi_eq inherits equalities from outer conjunctive levels.
Suppose we have a where condition of the following form: WHERE f1=f2 AND f3=f4 AND f3=f5 AND ... AND (...OR (f1=f3 AND ...)). In this case: f1=f2 will be substituted for Item_multi_eq(f1,f2); f3=f4 and f3=f5 will be substituted for Item_multi_eq(f3,f4,f5); f1=f3 will be substituted for Item_multi_eq(f1,f2,f3,f4,f5);
An object of the class Item_multi_eq can contain an optional constant item c. Then it represents a multiple equality of the form c=f1=...=fk.
Objects of the class Item_multi_eq are used for the following:
When feature 1 is supported they say that join transitive closure is employed. When feature 2 is supported they say that search argument transitive closure is employed. Both features are usually supported by preprocessing original query and adding additional predicates. We do not just add predicates, we rather dynamically replace some predicates that can not be used to access tables in the investigated plan for those, obtained by substitution of some fields for equal fields, that can be used.
Multiple equality objects are employed only at the optimize phase. Usually they are not supposed to be evaluated. Yet in some cases we call the method val_int() for them. We have to take care of restricting the predicate such an object represents f1=f2= ...=fn to the projection of known fields fi1=...=fik.
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Item_multi_eq::Item_multi_eq | ( | Item_field * | lhs_field, |
Item_field * | rhs_field | ||
) |
Item_multi_eq::Item_multi_eq | ( | Item * | const_item, |
Item_field * | field | ||
) |
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explicit |
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delete |
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delete |
void Item_multi_eq::add | ( | Item_field * | field | ) |
bool Item_multi_eq::add | ( | THD * | thd, |
Item * | const_item, | ||
Item_field * | field | ||
) |
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Wrap incompatible arguments in CAST nodes to the expected data types.
Reimplemented from Item.
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private |
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inlineoverridevirtual |
Reimplemented from Item.
Checks if the current constant value m_const_arg (that each field in fields needs to be equal to during execution) is the same as the provided constant item.
If that's not the case, it sets m_always_false to true as a field cannot be equal to different constant values at the same time.
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inline |
Returns the constant Item that this multi equality is equal to(if any).
bool Item_multi_eq::contains | ( | const Field * | field | ) | const |
Check whether a field is referred in the multiple equality.
The function checks whether field is occurred in the Item_multi_eq object .
field | field whose occurrence is to be checked |
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inlineoverridevirtual |
Whether this Item is an equi-join condition.
If this Item is a compound item (i.e. multiple condition AND'ed together), it will only return true if the Item contains only equi-join conditions AND'ed together. This is used to determine whether the condition can be used as a join condition for hash join (join conditions in hash join must be equi-join conditions), or if it should be placed as a filter after the join.
Reimplemented from Item_func.
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Provide a more specific equality check for a function.
Combine with Item::eq() to implement a complete equality check.
Reimplemented from Item_func.
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Reimplemented from Item.
Transform an Item_multi_eq object after having added a table that represents a materialized semi-join.
If the multiple equality represented by the Item_multi_eq object contains a field from the subquery that was used to create the materialized table, add the corresponding key field from the materialized table to the multiple equality.
Reimplemented from Item.
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Implements Item_func.
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inline |
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inline |
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temporary area used for constant folding
Get filtering effect for multiple equalities, i.e.
"tx.col = value_1 = ... = value_n" where value_i may be a constant, a column etc.
The multiple equality only contributes to the filtering effect for 'filter_for_table' if a) A column in 'filter_for_table' is referred to b) at least one value_i is a constant or a column in a table already read
If this multiple equality refers to more than one column in 'filter_for_table', the predicates on all these fields will contribute to the filtering effect.
Reimplemented from Item.
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inline |
Get the first field of multiple equality, use for semantic checking.
First | field in the multiple equality. |
Item_field * Item_multi_eq::get_subst_item | ( | const Item_field * | field | ) |
Get item that can be substituted for the supplied item.
field | field item to get substitution field for, which must be present within the multiple equality itself. |
Found | substitution item in the multiple equality. |
Get the first item of multiple equality that can be substituted for the given field item. In order to make semijoin materialization strategy work correctly we can't propagate equal fields between a materialized semijoin and the outer query (or any other semijoin) unconditionally. Thus the field is returned according to the following rules:
1) If the given field belongs to a materialized semijoin then the first field in the multiple equality which belongs to the same semijoin is returned. 2) If the given field doesn't belong to a materialized semijoin then the first field in the multiple equality is returned.
uint Item_multi_eq::members | ( | ) |
bool Item_multi_eq::merge | ( | THD * | thd, |
Item_multi_eq * | item | ||
) |
Add members of another Item_multi_eq object.
The function merges two multiple equalities. After this operation the Item_multi_eq object additionally contains the field items of another item of the type Item_multi_eq. If the optional constant items are not equal the m_always_false flag is set to true.
thd | thread handler |
item | multiple equality whose members are to be joined |
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delete |
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delete |
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This method is used for to:
For more information about view definition query, INFORMATION_SCHEMA query and why they should be generated from the Item-tree,
Reimplemented from Item.
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Resolve type-related information for this item, such as result field type, maximum size, precision, signedness, character set and collation.
Also check compatibility of argument types and return error when applicable. Also adjust nullability when applicable.
thd | thread handler |
Reimplemented from Item_bool_func.
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inlineoverridevirtual |
Reimplemented from Item_func.
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inline |
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inline |
Order field items in multiple equality according to a sorting criteria.
The function perform ordering of the field items in the Item_multi_eq object according to the criteria determined by the cmp callback parameter. If cmp(item_field1,item_field2,arg)<0 than item_field1 must be placed after item_field2.
The function sorts field items by the exchange sort algorithm. The list of field items is looked through and whenever two neighboring members follow in a wrong order they are swapped. This is performed again and again until we get all members in a right order.
compare | function to compare field item |
bool Item_multi_eq::update_const | ( | THD * | thd | ) |
Check appearance of new constant items in the multiple equality object.
The function checks appearance of new constant items among the members of multiple equalities. Each new constant item is compared with the designated constant item if there is any in the multiple equality. If there is none the first new constant item becomes designated.
thd | thread handler |
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Updates used tables, not null tables information and accumulates properties up the item tree, cf.
used_tables_cache, not_null_tables_cache and m_accum_properties.
TODO(sgunders): Consider just removing these caches; it causes a lot of bugs (cache invalidation is known to be a complex problem), and the performance benefits are dubious.
Reimplemented from Item.
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overridevirtual |
Traverses a tree of Items in prefix and/or postfix order.
Optionally walks into subqueries.
processor | processor function to be invoked per item returns true to abort traversal, false to continue |
walk | controls how to traverse the item tree enum_walk::PREFIX: call processor before invoking children enum_walk::POSTFIX: call processor after invoking children enum_walk::SUBQUERY go down into subqueries walk values are bit-coded and may be combined. Omitting both enum_walk::PREFIX and enum_walk::POSTFIX is undefined behaviour. |
arg | Optional pointer to a walk-specific object |
false | walk succeeded |
true | walk aborted by agreement, an error may have been reported |
Reimplemented from Item.
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Helper for comparing constants.
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Should constants be compared as datetimes?
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List of equal field items.
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Flag set to true if the equality is known to be always false.
Optional constant item equal to all the field items.