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Fixed bug in LEFT JOIN

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This commit is contained in:
monty@hundin.mysql.fi
2001-12-05 23:15:05 +02:00
parent 4b513347c4
commit 90004e340b
7 changed files with 126 additions and 33 deletions
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22
sql/sql_select.cc
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@@ -2119,10 +2119,17 @@ get_best_combination(JOIN *join)
j->type=JT_REF; /* Must read with repeat */
else if (ref_key == j->ref.key_copy)
{ /* Should never be reached */
j->type=JT_CONST; /* purecov: deadcode */
/*
This happen if we are using a constant expression in the ON part
of an LEFT JOIN.
SELECT * FROM a LEFT JOIN b ON b.key=30
Here we should not mark the table as a 'const' as a field may
have a 'normal' value or a NULL value.
*/
j->type=JT_CONST;
if (join->const_tables == tablenr)
{
join->const_tables++; /* purecov: deadcode */
join->const_tables++;
join->const_table_map|=form->map;
}
}
@@ -2251,7 +2258,7 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
used_tables|=current_map;
if (tab->type == JT_REF && tab->quick &&
tab->ref.key == tab->quick->index &&
(uint) tab->ref.key == tab->quick->index &&
tab->ref.key_length < tab->quick->max_used_key_length)
{
/* Range uses longer key; Use this instead of ref on key */
@@ -2689,8 +2696,8 @@ static void update_depend_map(JOIN *join, ORDER *order)
/*
** simple_order is set to 1 if sort_order only uses fields from head table
** and the head table is not a LEFT JOIN table
simple_order is set to 1 if sort_order only uses fields from head table
and the head table is not a LEFT JOIN table
*/
static ORDER *
@@ -4331,8 +4338,11 @@ join_read_const(JOIN_TAB *tab)
}
store_record(table,1);
}
else if (!table->status) // Only happens with left join
else if (!(table->status & ~STATUS_NULL_ROW)) // Only happens with left join
{
table->status=0;
restore_record(table,1); // restore old record
}
table->null_row=0;
return table->status ? -1 : 0;
}