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Bug #49512 : subquery with aggregate function crash

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subselect_single_select_engine::exec()

When a subquery doesn't need to be evaluated because
it returns only aggregate functions and these aggregates
can be calculated from the metadata about the table it
was not updating all the relevant members of the JOIN 
structure to reflect that this is a constant query.
This caused problems to the enclosing subquery 
('<> SOME' in the test case above) trying to read some
data about the tables.

Fixed by setting const_tables to the number of tables 
when the SELECT is optimized away.
This commit is contained in:
Georgi Kodinov
2009-12-23 17:11:22 +02:00
parent f79e182a9c
commit c968fd4818
3 changed files with 29 additions and 0 deletions
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sql/sql_select.cc
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@ -942,6 +942,7 @@ JOIN::optimize()
DBUG_PRINT("info",("Select tables optimized away"));
zero_result_cause= "Select tables optimized away";
tables_list= 0; // All tables resolved
const_tables= tables;
/*
Extract all table-independent conditions and replace the WHERE
clause with them. All other conditions were computed by opt_sum_query