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Fixed bug #28571. Outer join queries with ON conditions over

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constant outer tables did not return null complemented
rows when conditions were evaluated to FALSE.
Wrong results were returned because the conditions over constant
outer tables, when being pushed down, were erroneously enclosed 
into the guard function used for WHERE conditions.
This commit is contained in:
igor@olga.mysql.com
2007-05-26 10:33:01 -07:00
parent dc32ee5347
commit fbebb47efe
3 changed files with 60 additions and 25 deletions
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54
sql/sql_select.cc
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@ -5666,28 +5666,6 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
join->const_table_map,
(table_map) 0);
DBUG_EXECUTE("where",print_where(const_cond,"constants"););
for (JOIN_TAB *tab= join->join_tab+join->const_tables;
tab < join->join_tab+join->tables ; tab++)
{
if (*tab->on_expr_ref)
{
JOIN_TAB *cond_tab= tab->first_inner;
COND *tmp= make_cond_for_table(*tab->on_expr_ref,
join->const_table_map,
( table_map) 0);
if (!tmp)
continue;
tmp= new Item_func_trig_cond(tmp, &cond_tab->not_null_compl);
if (!tmp)
DBUG_RETURN(1);
tmp->quick_fix_field();
cond_tab->select_cond= !cond_tab->select_cond ? tmp :
new Item_cond_and(cond_tab->select_cond,tmp);
if (!cond_tab->select_cond)
DBUG_RETURN(1);
cond_tab->select_cond->quick_fix_field();
}
}
if (const_cond && !const_cond->val_int())
{
DBUG_PRINT("info",("Found impossible WHERE condition"));
@ -5918,13 +5896,39 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
}
/*
Push down all predicates from on expressions.
Each of these predicated are guarded by a variable
Push down conditions from all on expressions.
Each of these conditions are guarded by a variable
that turns if off just before null complemented row for
outer joins is formed. Thus, the predicates from an
outer joins is formed. Thus, the condition from an
'on expression' are guaranteed not to be checked for
the null complemented row.
*/
/* First push down constant conditions from on expressions */
for (JOIN_TAB *tab= join->join_tab+join->const_tables;
tab < join->join_tab+join->tables ; tab++)
{
if (*tab->on_expr_ref)
{
JOIN_TAB *cond_tab= tab->first_inner;
COND *tmp= make_cond_for_table(*tab->on_expr_ref,
join->const_table_map,
(table_map) 0);
if (!tmp)
continue;
tmp= new Item_func_trig_cond(tmp, &cond_tab->not_null_compl);
if (!tmp)
DBUG_RETURN(1);
tmp->quick_fix_field();
cond_tab->select_cond= !cond_tab->select_cond ? tmp :
new Item_cond_and(cond_tab->select_cond,tmp);
if (!cond_tab->select_cond)
DBUG_RETURN(1);
cond_tab->select_cond->quick_fix_field();
}
}
/* Push down non-constant conditions from on expressions */
JOIN_TAB *last_tab= tab;
while (first_inner_tab && first_inner_tab->last_inner == last_tab)
{