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|   | Query_result_union_direct (Query_result *result, Query_block *last_query_block) | 
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| bool  | change_query_result (THD *thd, Query_result *new_result) override | 
|   | Replace the current query result with new_result and prepare it.  More...
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| uint  | field_count (const mem_root_deque< Item * > &) const override | 
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| bool  | postponed_prepare (THD *thd, const mem_root_deque< Item * > &types) override | 
|   | Do prepare() if preparation has been postponed until column type information is computed (used by Query_result_union_direct).  More...
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| bool  | send_result_set_metadata (THD *, const mem_root_deque< Item * > &, uint) override | 
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| bool  | send_data (THD *, const mem_root_deque< Item * > &) override | 
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| bool  | start_execution (THD *thd) override | 
|   | Prepare for execution of the query expression or DML statement.  More...
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| bool  | send_eof (THD *) override | 
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| bool  | flush () override | 
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| bool  | check_supports_cursor () const override | 
|   | Check if this query result set supports cursors.  More...
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| void  | abort_result_set (THD *thd) override | 
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| void  | cleanup () override | 
|   | Cleanup after this execution.  More...
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|   | Query_result_union () | 
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| bool  | prepare (THD *thd, const mem_root_deque< Item * > &list, Query_expression *u) override | 
|   | Perform preparation specific to the query expression or DML statement.  More...
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| bool  | send_data (THD *thd, const mem_root_deque< Item * > &items) override | 
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| bool  | send_eof (THD *thd) override | 
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| void  | cleanup () override | 
|   | Cleanup after this execution.  More...
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| bool  | reset () override | 
|   | Reset and empty the temporary table that stores the materialized query result.  More...
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| bool  | create_result_table (THD *thd, const mem_root_deque< Item * > &column_types, bool is_distinct, ulonglong options, const char *alias, bool create_table, Query_term_set_op *op=nullptr) | 
|   | Create a temporary table to store the result of a query expression (used, among others, when materializing a UNION DISTINCT).  More...
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| uint  | get_hidden_field_count () const | 
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| bool  | skip_create_table () const | 
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| 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 implementing INTERSECT or EXCEPT: informs TableScanIterator::TableScanIterator how many rows to read from the materialized table.  More...
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|   | Query_result_interceptor () | 
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|   | Query_result () | 
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| virtual  | ~Query_result ()=default | 
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| virtual bool  | needs_file_privilege () const | 
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| virtual bool  | export_result_to_object_storage () const | 
|   | Returns true if the data has to be exported to object store.  More...
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| virtual bool  | need_explain_interceptor () const | 
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| virtual bool  | create_table_for_query_block (THD *) | 
|   | Create table, only needed to support CREATE TABLE ... SELECT.  More...
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| virtual bool  | use_protocol_adapter () const | 
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| virtual bool  | use_protocol_wrapper () const | 
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| virtual Server_side_cursor *  | cursor () const | 
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| virtual Table_ref *  | get_create_table () const | 
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This class is effectively dead. 
It was used for non-DISTINCT UNIONs in the pre-iterator executor. Now it exists only as a shell for certain setup tasks, and should be removed. 
 
  
  
      
        
          | bool Query_result_union_direct::start_execution  | 
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          THD *  | 
           | ) | 
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inlineoverridevirtual   | 
  
 
Prepare for execution of the query expression or DML statement. 
Generally, this will have an implementation only for outer-most Query_block objects, such as data change statements (for preparation of the target table(s)) or dump statements (for preparation of target file).
- Returns
 - false if success, true if error 
 
Reimplemented from Query_result.