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Bug#51242 HAVING clause on table join produce incorrect results

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The problem is that when we make conditon for
grouped result const part of condition is cut off.
It happens because some parts of 'having' condition
which refer to outer join become const after
make_join_statistics. These parts may be lost
during further having condition transformation
in JOIN::exec. The fix is adding 'having'
condition check for const tables after
make_join_statistics is performed.


mysql-test/r/having.result:
  test case
mysql-test/t/having.test:
  test result
sql/sql_select.cc:
  added 'having' condition check for const tables
  after make_join_statistics is performed.
This commit is contained in:
Sergey Glukhov 2010-03-19 13:09:22 +04:00
commit ad6e00e3b2
3 changed files with 90 additions and 0 deletions
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25
sql/sql_select.cc
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@ -1112,6 +1112,31 @@ JOIN::optimize()
{
conds=new Item_int((longlong) 0,1); // Always false
}
/*
It's necessary to check const part of HAVING cond as
there is a chance that some cond parts may become
const items after make_join_statisctics(for example
when Item is a reference to cost table field from
outer join).
This check is performed only for those conditions
which do not use aggregate functions. In such case
temporary table may not be used and const condition
elements may be lost during further having
condition transformation in JOIN::exec.
*/
if (having && !having->with_sum_func)
{
COND *const_cond= make_cond_for_table(having, const_table_map, 0);
DBUG_EXECUTE("where", print_where(const_cond, "const_having_cond",
QT_ORDINARY););
if (const_cond && !const_cond->val_int())
{
zero_result_cause= "Impossible HAVING noticed after reading const tables";
DBUG_RETURN(0);
}
}
if (make_join_select(this, select, conds))
{
zero_result_cause=