MySQL 8.4.3
Source Code Documentation
sql_union.h
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23
24#ifndef SQL_UNION_INCLUDED
25#define SQL_UNION_INCLUDED
26
27#include <sys/types.h>
28
29#include "my_inttypes.h"
30#include "sql/query_result.h" // Query_result_interceptor
31#include "sql/table.h"
32#include "sql/temp_table_param.h" // Temp_table_param
33
34class Item;
36class THD;
37template <class Element_type>
38class mem_root_deque;
39
41 protected:
43
44 public:
46
48 bool prepare(THD *thd, const mem_root_deque<Item *> &list,
49 Query_expression *u) override;
50 /**
51 Do prepare() if preparation has been postponed until column type
52 information is computed (used by Query_result_union_direct).
53
54 @param thd Thread handle
55 @param types Column types
56
57 @return false on success, true on failure
58 */
59 virtual bool postponed_prepare(THD *thd [[maybe_unused]],
60 const mem_root_deque<Item *> &types
61 [[maybe_unused]]) {
62 return false;
63 }
64 bool send_data(THD *thd, const mem_root_deque<Item *> &items) override;
65 bool send_eof(THD *thd) override;
66 virtual bool flush();
67 void cleanup() override { (void)reset(); }
68 bool reset() override;
69 bool create_result_table(THD *thd, const mem_root_deque<Item *> &column_types,
70 bool is_distinct, ulonglong options,
71 const char *alias, bool bit_fields_as_long,
72 bool create_table, Query_term_set_op *op = nullptr);
77 }
79
80 /// Set an effective LIMIT for the number of rows coming out of a materialized
81 /// temporary table used for implementing INTERSECT or EXCEPT: informs
82 /// TableScanIterator::TableScanIterator how many rows to read from the
83 /// materialized table. For UNION and simple tables the limitation is enforced
84 /// earlier, at materialize time, but this is not possible for INTERSECT and
85 /// EXCEPT due to the use of cardinality counters.
86 ///
87 /// @param limit_rows the effective limit, or HA_POS_ERROR if none.
88 void set_limit(ha_rows limit_rows) override;
89
90 // For assignment of tmp_table_param for CTE clones
91 friend class Common_table_expr;
92};
93
94#endif /* SQL_UNION_INCLUDED */
Kerberos Client Authentication nullptr
Definition: auth_kerberos_client_plugin.cc:251
After parsing, a Common Table Expression is accessed through a Table_ref.
Definition: table.h:4428
Base class that is used to represent any kind of expression in a relational query.
Definition: item.h:936
This class represents a query expression (one query block or several query blocks combined with UNION...
Definition: sql_lex.h:626
Definition: query_result.h:181
Definition: sql_union.h:40
Query_result_union()
Definition: sql_union.h:47
bool reset() override
Reset and empty the temporary table that stores the materialized query result.
Definition: sql_union.cc:245
bool skip_create_table() const
Definition: sql_union.h:78
virtual bool postponed_prepare(THD *thd, const mem_root_deque< Item * > &types)
Do prepare() if preparation has been postponed until column type information is computed (used by Que...
Definition: sql_union.h:59
Temp_table_param tmp_table_param
Definition: sql_union.h:42
virtual bool flush()
Definition: sql_union.cc:139
bool create_result_table(THD *thd, const mem_root_deque< Item * > &column_types, bool is_distinct, ulonglong options, const char *alias, bool bit_fields_as_long, bool create_table, Query_term_set_op *op=nullptr)
Create a temporary table to store the result of a query expression (used, among others,...
Definition: sql_union.cc:167
bool send_data(THD *thd, const mem_root_deque< Item * > &items) override
Definition: sql_union.cc:113
uint get_hidden_field_count() const
Definition: sql_union.h:75
TABLE * table
Definition: sql_union.h:45
void set_limit(ha_rows limit_rows) override
Set an effective LIMIT for the number of rows coming out of a materialized temporary table used for i...
Definition: sql_union.cc:249
bool prepare(THD *thd, const mem_root_deque< Item * > &list, Query_expression *u) override
Perform preparation specific to the query expression or DML statement.
Definition: sql_union.cc:107
void cleanup() override
Cleanup after this execution.
Definition: sql_union.h:67
bool send_eof(THD *thd) override
Definition: sql_union.cc:137
Common base class for n-ary set operations, including unary.
Definition: query_term.h:402
For each client connection we create a separate thread with THD serving as a thread/connection descri...
Definition: sql_lexer_thd.h:36
bool optimize_derived(THD *thd)
Optimize the query expression representing a derived table/view.
Definition: sql_derived.cc:1635
bool create_materialized_table(THD *thd)
Create result table for a materialized derived table/view.
Definition: sql_derived.cc:1683
Object containing parameters used when creating and using temporary tables.
Definition: temp_table_param.h:95
uint hidden_field_count
Definition: temp_table_param.h:133
bool skip_create_table
true <=> don't actually create table handler when creating the result table.
Definition: temp_table_param.h:176
A (partial) implementation of std::deque allocating its blocks on a MEM_ROOT.
Definition: mem_root_deque.h:111
PFS_table * create_table(PFS_table_share *share, PFS_thread *opening_thread, const void *identity)
Create instrumentation for a table instance.
Definition: pfs_instr.cc:1308
my_off_t ha_rows
Definition: my_base.h:1141
Some integer typedefs for easier portability.
unsigned long long int ulonglong
Definition: my_inttypes.h:56
Definition: options.cc:57
std::list< T, ut::allocator< T > > list
Specialization of list which uses ut_allocator.
Definition: ut0new.h:2879
Definition: table.h:1406