MySQL 8.0.32
Source Code Documentation
Item_asterisk Class Reference

Represents [schema. More...

#include <item.h>

Inheritance diagram for Item_asterisk:

Public Member Functions

 Item_asterisk (const POS &pos, const char *opt_schema_name, const char *opt_table_name)
 Constructor. More...
bool itemize (Parse_context *pc, Item **res) override
 The same as contextualize() but with additional parameter. More...
bool fix_fields (THD *, Item **) override
 Resolve the name of a column reference. More...
bool is_asterisk () const override
 Checks if the current object represents an asterisk select list item. More...
- Public Member Functions inherited from Item_field
void set_item_equal (Item_equal *item_equal_arg)
void set_item_equal_all_join_nests (Item_equal *item_equal)
 Item_field (Name_resolution_context *context_arg, const char *db_arg, const char *table_name_arg, const char *field_name_arg)
 Constructor used for internal information queries. More...
 Item_field (const POS &pos, const char *db_arg, const char *table_name_arg, const char *field_name_arg)
 Used from parser to construct column references. More...
 Item_field (THD *thd, Item_field *item)
 Used to create a copy (clone) of another Item_field. More...
 Item_field (THD *thd, Name_resolution_context *context_arg, Table_ref *tr, Field *field)
 Constructor used inside setup_wild(). More...
 Item_field (Field *field)
 Create column reference based on a table field. More...
enum Type type () const override
bool eq (const Item *item, bool binary_cmp) const override
double val_real () override
longlong val_int () override
longlong val_time_temporal () override
 Return time value of item in packed longlong format. More...
longlong val_date_temporal () override
 Return date value of item in packed longlong format. More...
longlong val_time_temporal_at_utc () override
longlong val_date_temporal_at_utc () override
my_decimalval_decimal (my_decimal *) override
Stringval_str (String *) override
bool val_json (Json_wrapper *result) override
 Get a JSON value from an Item. More...
bool send (Protocol *protocol, String *str_arg) override
 This is only called from items that is not of type item_field. More...
void reset_field (Field *f)
 Reset this item to point to a field from the new temporary table. More...
void make_field (Send_field *tmp_field) override
void save_org_in_field (Field *field) override
 Set a field's value from a item. More...
table_map used_tables () const override
Item_result result_type () const override
Item_result numeric_context_result_type () const override
 Result type when an item appear in a numeric context. More...
TYPELIBget_typelib () const override
 Get the typelib information for an item of type set or enum. More...
Item_result cast_to_int_type () const override
enum_monotonicity_info get_monotonicity_info () const override
longlong val_int_endpoint (bool left_endp, bool *incl_endp) override
void set_result_field (Field *field_arg) override
Fieldget_tmp_table_field () override
 If this Item is being materialized into a temporary table, returns the field that is being materialized into. More...
Fieldtmp_table_field (TABLE *) override
void set_base_item_field (const Item_field *item)
const Item_fieldbase_item_field () const
bool get_date (MYSQL_TIME *ltime, my_time_flags_t fuzzydate) override
bool get_time (MYSQL_TIME *ltime) override
bool get_timeval (my_timeval *tm, int *warnings) override
 Get timestamp in "struct timeval" format. More...
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...
Itemget_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...
bool collect_item_field_processor (uchar *arg) override
 Store the pointer to this item field into a list if not already there. More...
bool collect_item_field_or_ref_processor (uchar *arg) override
bool collect_item_field_or_view_ref_processor (uchar *arg) override
 Collects fields and view references that have the qualifying table in the specified query block. More...
bool add_field_to_set_processor (uchar *arg) override
 Item::walk function. More...
bool add_field_to_cond_set_processor (uchar *) override
 Item::walk function. More...
bool remove_column_from_bitmap (uchar *arg) override
 Visitor interface for removing all column expressions (Item_field) in this expression tree from a bitmap. More...
bool find_item_in_field_list_processor (uchar *arg) override
 Check if an Item_field references some field from a list of fields. More...
bool find_field_processor (uchar *arg) override
 Is this an Item_field which references the given Field argument? More...
bool check_function_as_value_generator (uchar *args) override
 Check if this item is allowed for a virtual column or inside a default expression. More...
bool mark_field_in_map (uchar *arg) override
 Mark underlying field in read or write map of a table. More...
bool used_tables_for_level (uchar *arg) override
 Return used table information for the specified query block (level). More...
bool check_column_privileges (uchar *arg) override
 Check privileges of base table column. More...
bool check_partition_func_processor (uchar *) override
 Check if a partition function is allowed. More...
void bind_fields () override
 Bind objects from the current execution context to field objects in item trees. 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 this column is found in PARTITION clause of all the window functions. More...
bool check_column_in_group_by (uchar *arg) override
 Check if this column is found in GROUP BY. More...
Itemreplace_with_derived_expr (uchar *arg) override
 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...
Itemreplace_with_derived_expr_ref (uchar *arg) override
 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...
void cleanup () override
 Called for every Item after use (preparation and execution). More...
void reset_field ()
 Reset all aspect of a field object, so that it can be re-resolved. More...
Item_equalfind_item_equal (COND_EQUAL *cond_equal) const
 Find a field among specified multiple equalities. More...
bool subst_argument_checker (uchar **arg) override
 Check whether a field can be substituted by an equal item. More...
Itemequal_fields_propagator (uchar *arg) override
 If field matches a multiple equality, set a pointer to that object in the field. More...
Itemreplace_item_field (uchar *) override
 If this field is the target is the target of replacement, replace it with the info object's item or, if the item is found inside a subquery, the target is an outer reference, so we create a new Item_field, mark it accordingly and replace with that instead. More...
bool disable_constant_propagation (uchar *) override
Itemreplace_equal_field (uchar *) override
 Replace an Item_field for an equal Item_field that evaluated earlier (if any). More...
uint32 max_disp_length ()
Item_fieldfield_for_view_update () override
Itemsafe_charset_converter (THD *thd, const CHARSET_INFO *tocs) override
int fix_outer_field (THD *thd, Field **field, Item **reference)
 Resolve the name of an outer select column reference. More...
Itemupdate_value_transformer (uchar *select_arg) override
 Add the field to the select list and substitute it for the reference to the field. More...
void print (const THD *thd, String *str, enum_query_type query_type) const override
 This method is used for to: More...
bool is_outer_field () const override
Field::geometry_type get_geometry_type () const override
const CHARSET_INFOcharset_for_protocol (void) override
void dbug_print () const
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
 Calculate condition filtering effect for "WHERE field", which implicitly means "WHERE field <> 0". More...
float get_cond_filter_default_probability (double max_distinct_values, float default_filter) const
 Returns the probability for the predicate "col OP <val>" to be true for a row in the case where no index statistics or range estimates are available for 'col'. More...
bool alias_name_used () const override
bool repoint_const_outer_ref (uchar *arg) override
 If this object is the real_item of an Item_ref, repoint the result_field to field. More...
bool returns_array () const override
 Whether the item returns array of its data type. More...
void set_can_use_prefix_key () override
bool replace_field_processor (uchar *arg) override
 A processor that replaces any Fields with a Create_field_wrapper. More...
bool strip_db_table_name_processor (uchar *) override
 Generated fields don't need db/table names. More...
- Public Member Functions inherited from Item_ident
 Item_ident (Name_resolution_context *context_arg, const char *db_name_arg, const char *table_name_arg, const char *field_name_arg)
 Item_ident (const POS &pos, const char *db_name_arg, const char *table_name_arg, const char *field_name_arg)
 Item_ident (THD *thd, Item_ident *item)
 Constructor used by Item_field & Item_*_ref (see Item comment) More...
const char * full_name () const override
void set_orignal_db_name (const char *name_arg)
void set_original_table_name (const char *name_arg)
void set_original_field_name (const char *name_arg)
const char * original_db_name () const
const char * original_table_name () const
const char * original_field_name () const
bool aggregate_check_distinct (uchar *arg) override
bool aggregate_check_group (uchar *arg) override
Bool3 local_column (const Query_block *sl) const override
 Tells if this is a column of a table whose qualifying query block is 'sl'. More...
bool change_context_processor (uchar *arg) override
bool is_alias_of_expr () const
void set_alias_of_expr ()
 Marks that this Item's name is alias of SELECT expression. More...
bool walk (Item_processor processor, enum_walk walk, uchar *arg) override
 Traverses a tree of Items in prefix and/or postfix order. More...
bool update_depended_from (uchar *) override
bool is_strong_side_column_not_in_fd (uchar *arg) override
bool is_column_not_in_fd (uchar *arg) override
- Public Member Functions inherited from Item
 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
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 Fieldmake_string_field (TABLE *table) const
 Create a field to hold a string value from an item. More...
void quick_fix_field ()
virtual bool propagate_type (THD *thd, const Type_properties &type)
 Propagate data type specifications into parameters and user variables. More...
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< ContainedSubqueryget_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...
bool evaluate (THD *thd, String *str)
 Evaluate item, possibly using the supplied buffer. 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_bool ()
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 (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_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 ()
 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...
void aggregate_type (Bounds_checked_array< Item * > items)
 Aggregates data types from array of items into current item. 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 Stringval_str_ascii (String *str)
virtual bool val_bool ()
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_decimalerror_decimal (my_decimal *decimal_value)
 Get the value to return from val_decimal() in case of errors. More...
Stringerror_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 table_map not_null_tables () const
 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...
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 Itemclone_item () const
virtual cond_result eq_cmp_result () const
uint float_length (uint decimals_par) const
virtual uint decimal_precision () 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, bool used_alias) const
 Prints the item when it's part of ORDER BY and GROUP BY. More...
virtual void update_used_tables ()
 Updates used tables, not null tables information and accumulates properties up the item tree, cf. More...
virtual void split_sum_func (THD *, Ref_item_array, mem_root_deque< Item * > *)
void split_sum_func2 (THD *thd, Ref_item_array ref_item_array, mem_root_deque< Item * > *fields, Item **ref, bool skip_registered)
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 bool is_result_field () const
virtual Fieldget_result_field () const
virtual bool is_bool_func () const
virtual void no_rows_in_result ()
virtual Itemcopy_or_same (THD *)
virtual Itemcopy_andor_structure (THD *)
virtual Itemreal_item ()
virtual const Itemreal_item () const
virtual const CHARSET_INFOcompare_collation () const
template<class T >
auto walk_helper_thunk (uchar *arg)
template<class T >
auto analyze_helper_thunk (uchar **arg)
 See CompileItem. More...
virtual Itemtransform (Item_transformer transformer, uchar *arg)
 Perform a generic transformation of the Item tree, by adding zero or more additional Item objects to it. More...
virtual Itemcompile (Item_analyzer analyzer, uchar **arg_p, Item_transformer transformer, uchar *arg_t)
 Perform a generic "compilation" of the Item tree, ie transform the Item tree by adding zero or more Item objects to it. More...
virtual void traverse_cond (Cond_traverser traverser, void *arg, traverse_order)
virtual bool intro_version (uchar *)
bool cleanup_processor (uchar *)
 cleanup() item if it is resolved ('fixed'). More...
virtual bool visitor_processor (uchar *arg)
 A processor to handle the select lex visitor framework. More...
virtual bool find_item_processor (uchar *arg)
virtual bool is_non_const_over_literals (uchar *)
virtual bool cast_incompatible_args (uchar *)
 Wrap incompatible arguments in CAST nodes to the expected data types. More...
virtual bool reset_wf_state (uchar *arg)
 Reset execution state for such window function types as determined by arg. More...
virtual bool inform_item_in_cond_of_tab (uchar *)
virtual bool clean_up_after_removal (uchar *arg)
 Clean up after removing the item from the item tree. More...
virtual bool collect_scalar_subqueries (uchar *)
virtual bool collect_grouped_aggregates (uchar *)
virtual bool collect_subqueries (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...
Itemcache_const_expr_transformer (uchar *item)
 Cache item if needed. More...
virtual bool equality_substitution_analyzer (uchar **)
virtual Itemequality_substitution_transformer (uchar *)
virtual bool explain_subquery_checker (uchar **)
virtual Itemexplain_subquery_propagator (uchar *)
virtual bool check_valid_arguments_processor (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 Itemreplace_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 Itemthis_item ()
virtual const Itemthis_item () const
virtual Item ** this_item_addr (THD *, Item **addr_arg)
virtual uint cols () const
virtual Itemelement_index (uint)
virtual Item ** addr (uint)
virtual bool check_cols (uint c)
virtual bool null_inside ()
virtual void bring_value ()
Fieldtmp_table_field_from_field_type (TABLE *table, bool fixed_length) const
 Create a field based on field_type of argument. More...
virtual Itemtruth_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 Itemreplace_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 Itemreplace_item_view_ref (uchar *)
virtual Itemreplace_aggregate (uchar *)
virtual Itemreplace_outer_ref (uchar *)
virtual bool update_aggr_refs (uchar *)
 A walker processor overridden by Item_aggregate_ref, q.v. More...
void delete_self ()
 Delete this item. More...
virtual bool is_splocal () const
virtual Settable_routine_parameterget_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...
Stringcheck_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, bool binary_cmp, const CHARSET_INFO *cs)
virtual bool is_expensive ()
uint32 max_char_length () const
uint32 max_char_length (const CHARSET_INFO *cs) const
void fix_char_length (uint32 max_char_length_arg)
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...
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_rollup_expr () const
void set_rollup_expr ()
 Set the property: this item (tree) contains a reference to a ROLLUP expr. More...
bool has_grouping_func () const
void set_grouping_func ()
 Set the property: this item is a call to GROUPING. More...
virtual bool created_by_in2exists () const
 Whether this Item was created by the IN->EXISTS subquery transformation. More...
void mark_subqueries_optimized_away ()
virtual bool gc_subst_analyzer (uchar **)
 Analyzer function for GC substitution. More...
virtual Itemgc_subst_transformer (uchar *)
 Transformer function for GC substitution. 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_decimal_properties (Item **item, uint nitems)
 Set precision and decimals of function when this depends on arguments' values for these quantities. More...
void aggregate_float_properties (Item **item, 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_char_length (Item **args, uint nitems)
 Set the maximum number of characters required by any of the items in args. More...
void aggregate_temporal_properties (Item **item, uint nitems)
 Set fractional seconds precision for temporal functions. More...
bool aggregate_string_properties (const char *name, Item **item, uint nitems)
 Aggregate string properties (character set, collation and maximum length) for string function. More...
void aggregate_num_type (Item_result result_type, Item **item, uint nitems)
 This function is used to resolve type for numeric result type of CASE, COALESCE, IF and LEAD/LAG. More...
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 void allow_array_cast ()
 A helper function to ensure proper usage of CAST(. More...
- Public Member Functions inherited from Parse_tree_node_tmpl< Context >
virtual ~Parse_tree_node_tmpl ()=default
bool is_contextualized () const
virtual bool contextualize (Context *pc)
 Do all context-sensitive things and mark the node as contextualized. More...
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...

Private Types

typedef Item_field super

Additional Inherited Members

- Public Types inherited from Item
enum  Type {
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 ,
 < Modifier for result transformation More...
enum  item_marker {
 < Values for member 'marker' More...
- Public Types inherited from Parse_tree_node_tmpl< Context >
typedef Context context_t
- Static Public Member Functions inherited from Item
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_INFOdefault_charset ()
- Static Public Member Functions inherited from Parse_tree_node_tmpl< Context >
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
- Public Attributes inherited from Item_field
 Table containing this resolved field. More...
 Source field. More...
Item_equalitem_equal {nullptr}
 Used during optimization to perform multiple equality analysis, this analysis should be performed during preparation instead, so that Item_field can be const after preparation. More...
uint16 field_index
 Index for this field in table->field array. More...
Item_equalitem_equal_all_join_nests {nullptr}
bool no_constant_propagation {false}
 If true, the optimizer's constant propagation will not replace this item with an equal constant. More...
uint have_privileges
bool any_privileges
bool can_use_prefix_key {false}
- Public Attributes inherited from Item_ident
 For regularly resolved column references, 'context' points to a name resolution context object belonging to the query block which simply contains the reference. More...
const char * db_name
 Schema name of the base table or view the column is part of. More...
const char * table_name
 If column is from a non-aliased base table or view, name of base table or view. More...
const char * field_name
 If column is aliased, the column alias name. More...
- Public Attributes inherited from Item
 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...
- Protected Member Functions inherited from Item_field
void set_field (Field *field)
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...
type_conversion_status save_in_field_inner (Field *field, bool no_conversions) override
 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...
- Protected Member Functions inherited from Item_ident
void print (const THD *thd, String *str, enum_query_type query_type, const char *db_name_arg, const char *table_name_arg) const
 Function to print column name for a table. More...
- Protected Member Functions inherited from Item
Stringmake_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...
Stringval_string_from_real (String *str)
Stringval_string_from_int (String *str)
Stringval_string_from_decimal (String *str)
Stringval_string_from_date (String *str)
Stringval_string_from_datetime (String *str)
Stringval_string_from_time (String *str)
my_decimalval_decimal_from_real (my_decimal *decimal_value)
my_decimalval_decimal_from_int (my_decimal *decimal_value)
my_decimalval_decimal_from_string (my_decimal *decimal_value)
my_decimalval_decimal_from_date (my_decimal *decimal_value)
my_decimalval_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...
Stringnull_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...
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...
- Protected Member Functions inherited from Parse_tree_node_tmpl< Context >
 Parse_tree_node_tmpl ()
- Static Protected Member Functions inherited from Item
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...
- Protected Attributes inherited from Item_ident
const char * m_orig_db_name
 The fields m_orig_db_name, m_orig_table_name and m_orig_field_name are maintained so that we can provide information about the origin of a column that may have been renamed within the query, e.g. More...
const char * m_orig_table_name
 Names the original table that is the source of the field. More...
const char * m_orig_field_name
 Names the field in the source base table. More...
bool m_alias_of_expr
 if this Item's name is alias of SELECT expression More...
- Protected Attributes inherited from Item
String str_value
 str_values's main purpose is to cache the value in save_in_field More...
uint8 m_accum_properties
- Static Protected Attributes inherited from Item
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_ROLLUP_EXPR = 0x10
 Set if the item or one or more of the underlying items contains a ROLLUP expression. 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...

Detailed Description

Represents [schema.

][table.]* in a select list

Item_asterisk is used to insert placeholder objects for the special select list item * (asterisk) into AST. Those placeholder objects are to be substituted later with e.g. a list of real table columns by a resolver (

See also

Member Typedef Documentation

◆ super

Constructor & Destructor Documentation

◆ Item_asterisk()

Item_asterisk::Item_asterisk ( const POS pos,
const char *  opt_schema_name,
const char *  opt_table_name 


posLocation of the * (asterisk) lexeme.
opt_schema_nameSchema name or nullptr.
opt_table_nameTable name or nullptr.

Member Function Documentation

◆ fix_fields()

bool Item_asterisk::fix_fields ( THD thd,
Item **  reference 

Resolve the name of a column reference.

The method resolves the column reference represented by 'this' as a column present in one of: FROM clause, SELECT clause, GROUP BY clause of a query Q, or in outer queries that contain Q.

The name resolution algorithm used is (where [T_j] is an optional table name that qualifies the column name):

search for a column or derived column named col_ref_i
[in table T_j] in the FROM clause of Q;
if such a column is NOT found AND // Lookup in outer queries.
there are outer queries
for each outer query Q_k beginning from the inner-most one
search for a column or derived column named col_ref_i
[in table T_j] in the FROM clause of Q_k;
if such a column is not found
Search for a column or derived column named col_ref_i
[in table T_j] in the SELECT and GROUP clauses of Q_k.
static char * query
const std::string SELECT("SELECT")
Name of the static privileges.
Definition: sql_yacc.h:242

Notice that compared to Item_ref::fix_fields, here we first search the FROM clause, and then we search the SELECT and GROUP BY clauses.

For the case where a table reference is already set for the field, we just need to make a call to set_field(). This is true for a cloned field used during condition pushdown to derived tables. A cloned field inherits table reference, depended_from, cached_table, context and field from the original field. set_field() ensures all other members are set correctly.

[in]thdcurrent thread
[in,out]referenceview column if this item was resolved to a view column
Return values
trueif error
falseon success

Reimplemented from Item_field.

◆ is_asterisk()

bool Item_asterisk::is_asterisk ( ) const

Checks if the current object represents an asterisk select list item.

false if a regular column reference, true if an asterisk select list item.

Reimplemented from Item_field.

◆ itemize()

bool Item_asterisk::itemize ( Parse_context pc,
Item **  res 

The same as contextualize() but with additional parameter.

This function finalize the construction of Item objects (see the Item(POS) constructor): we can access/change parser contexts from the itemize() function.

pccurrent parse context
[out]respointer to "this" or to a newly allocated replacement object to use in the Item tree instead
Return values
truesyntax/OOM/etc error

Reimplemented from Item_field.

The documentation for this class was generated from the following files: