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Fix for BUG#14662: view column in ORDER BY considered ambiguous if SELECT contains

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the same column as an aliased and as a non-aliased column.

The problem was that Item_direct_view_ref::eq() was first comparing view columns
by name, and in this case the name of one of them is different since it is aliased.


mysql-test/r/select.result:
  Added test for BUG#14662.
mysql-test/t/select.test:
  Added test for BUG#14662.
sql/item.cc:
  Changed the way view column refenreces are compared. Two view columns are
  equal if they resolve to the same result field of a view.
This commit is contained in:
unknown
2005-11-11 11:40:35 +02:00
parent 50ab764829
commit 9a0da055fd
3 changed files with 82 additions and 11 deletions
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42
mysql-test/r/select.result
View File

@ -3241,3 +3241,45 @@ f1 f2
Warnings:
Warning 1292 Incorrect date value: '2005-09-3a' for column 'f2' at row 1
drop table t1;
create table t1 (f1 int, f2 int);
insert into t1 values (1, 30), (2, 20), (3, 10);
create algorithm=merge view v1 as select f1, f2 from t1;
create algorithm=merge view v2 (f2, f1) as select f1, f2 from t1;
create algorithm=merge view v3 as select t1.f1 as f2, t1.f2 as f1 from t1;
select t1.f1 as x1, f1 from t1 order by t1.f1;
x1 f1
1 1
2 2
3 3
select v1.f1 as x1, f1 from v1 order by v1.f1;
x1 f1
1 1
2 2
3 3
select v2.f1 as x1, f1 from v2 order by v2.f1;
x1 f1
10 10
20 20
30 30
select v3.f1 as x1, f1 from v3 order by v3.f1;
x1 f1
10 10
20 20
30 30
select f1, f2, v1.f1 as x1 from v1 order by v1.f1;
f1 f2 x1
1 30 1
2 20 2
3 10 3
select f1, f2, v2.f1 as x1 from v2 order by v2.f1;
f1 f2 x1
10 3 10
20 2 20
30 1 30
select f1, f2, v3.f1 as x1 from v3 order by v3.f1;
f1 f2 x1
10 3 10
20 2 20
30 1 30
drop table t1;
drop view v1, v2, v3;

20
mysql-test/t/select.test
View File

@ -2729,3 +2729,23 @@ select * from t1 where f2 >= '2005-09-3a';
select * from t1 where f2 <= '2005-09-31';
select * from t1 where f2 <= '2005-09-3a';
drop table t1;
#
# Bug ##14662 ORDER BY on column of a view, with an alias of the same
# column causes ambiguous
#
create table t1 (f1 int, f2 int);
insert into t1 values (1, 30), (2, 20), (3, 10);
create algorithm=merge view v1 as select f1, f2 from t1;
create algorithm=merge view v2 (f2, f1) as select f1, f2 from t1;
create algorithm=merge view v3 as select t1.f1 as f2, t1.f2 as f1 from t1;
select t1.f1 as x1, f1 from t1 order by t1.f1;
select v1.f1 as x1, f1 from v1 order by v1.f1;
select v2.f1 as x1, f1 from v2 order by v2.f1;
select v3.f1 as x1, f1 from v3 order by v3.f1;
select f1, f2, v1.f1 as x1 from v1 order by v1.f1;
select f1, f2, v2.f1 as x1 from v2 order by v2.f1;
select f1, f2, v3.f1 as x1 from v3 order by v3.f1;
drop table t1;
drop view v1, v2, v3;

31
sql/item.cc
View File

@ -4938,8 +4938,7 @@ bool Item_direct_view_ref::fix_fields(THD *thd, Item **reference)
}
/*
Compare view field's name with item's name before call to referenced
item's eq()
Compare two view column references for equality.
SYNOPSIS
Item_direct_view_ref::eq()
@ -4947,12 +4946,13 @@ bool Item_direct_view_ref::fix_fields(THD *thd, Item **reference)
binary_cmp make binary comparison
DESCRIPTION
Consider queries:
create view v1 as select t1.f1 as f2, t1.f2 as f1 from t1;
select * from v1 order by f1;
In order to choose right field for sorting we need to compare
given item's name (f1) to view field's name prior to calling
referenced item's eq().
A view column reference is considered equal to another column
reference if the second one is a view column and if both column
references point to the same field. For views 'same field' means
the same Item_field object in the view translation table, where
the view translation table contains all result columns of the
view. This definition ensures that view columns are resolved
in the same manner as table columns.
RETURN
TRUE Referenced item is equal to given item
@ -4962,9 +4962,18 @@ bool Item_direct_view_ref::fix_fields(THD *thd, Item **reference)
bool Item_direct_view_ref::eq(const Item *item, bool binary_cmp) const
{
Item *it= ((Item *) item)->real_item();
return (!it->name || !my_strcasecmp(system_charset_info, it->name,
field_name)) && ref && (*ref)->real_item()->eq(it, binary_cmp);
if (item->type() == REF_ITEM)
{
Item_ref *item_ref= (Item_ref*) item;
if (item_ref->ref_type() == VIEW_REF)
{
Item *item_ref_ref= *(item_ref->ref);
DBUG_ASSERT((*ref)->type() == FIELD_ITEM &&
(item_ref_ref->type() == FIELD_ITEM));
return (*ref == item_ref_ref);
}
}
return FALSE;
}
void Item_null_helper::print(String *str)