Commit 476ca52e authored by unknown's avatar unknown
Browse files

Fix for BUG#11211 "GROUP BY doesn't work correctly" 

  
When the GROUP BY clause contains a column reference that can be resolved to
both an aliased column in the SELECT list, and to a column in the FROM clause,
the group column is resolved to the column in the FROM clause (for ANSI conformance).
However, it may be so that the user's intent is just the other way around, and he/she
gets the query results grouped by a completely different column than expexted.
This patch adds a warning in such cases that tells the user that there is potential
ambiguity in the group column.

sql/sql_select.cc
- Added a warning when a GROUP column is ambiguous due to that there is a
  column reference with the same name both in the SELECT and FROM clauses.
  In this case we resolve to the column in FROM clause and warn the user
  of a possible ambiguity.
- More extensive comments.
- Changed the function to return bool instead of int (as in other places).

mysql-test/t/group_by.test
  Added test for BUG#11211.

mysql-test/r/group_by.result
  Added test for BUG#11211.


mysql-test/r/group_by.result:
  Import patch 11211.diff
mysql-test/t/group_by.test:
  Import patch 11211.diff
sql/sql_select.cc:
  Import patch 11211.diff
BitKeeper/etc/ignore:
  Added ndb/src/dummy.cpp to the ignore list
mysql-test/r/alias.result:
  Added warning for potentially ambiguous column.
mysql-test/r/having.result:
  Added warning for potentially ambiguous column.
parent 894fd6ae

.bzrignore

+1 −0
Original line number Diff line number Diff line
@@ -1116,3 +1116,4 @@ vio/test-ssl 
vio/test-sslclient

vio/test-sslserver

vio/viotest-ssl

ndb/src/dummy.cpp

mysql-test/r/alias.result

+2 −0
Original line number Diff line number Diff line
@@ -58,6 +58,8 @@ INSERT INTO t1 VALUES (3359362,406,3359362,'Mustermann Musterfrau',7001,'2000-05 
SELECT ELT(FIELD(kundentyp,'PP','PPA','PG','PGA','FK','FKA','FP','FPA','K','KA','V','VA',''), 'Privat (Private Nutzung)','Privat (Private Nutzung) Sitz im Ausland','Privat (geschaeftliche Nutzung)','Privat (geschaeftliche Nutzung) Sitz im Ausland','Firma (Kapitalgesellschaft)','Firma (Kapitalgesellschaft) Sitz im Ausland','Firma (Personengesellschaft)','Firma (Personengesellschaft) Sitz im Ausland','oeff. rechtl. Koerperschaft','oeff. rechtl. Koerperschaft Sitz im Ausland','Eingetragener Verein','Eingetragener Verein Sitz im Ausland','Typ unbekannt') AS Kundentyp ,kategorie FROM t1 WHERE hdl_nr < 2000000 AND kategorie IN ('Prepaid','Mobilfunk') AND st_klasse = 'Workflow' GROUP BY kundentyp ORDER BY kategorie;

Kundentyp	kategorie

Privat (Private Nutzung)	Mobilfunk

Warnings:

Warning	1052	Column 'kundentyp' in group statement is ambiguous

drop table t1;

CREATE TABLE t1 (

AUFNR varchar(12) NOT NULL default '',

mysql-test/r/group_by.result

+24 −0
Original line number Diff line number Diff line
@@ -722,3 +722,27 @@ WHERE hostname LIKE '%aol%' 
    GROUP BY hostname;

hostname	no

cache-dtc-af05.proxy.aol.com	1

drop table if exists t1, t2;

Warnings:

Note	1051	Unknown table 't2'

create table t1 (c1 char(3), c2 char(3));

create table t2 (c3 char(3), c4 char(3));

insert into t1 values ('aaa', 'bb1'), ('aaa', 'bb2');

insert into t2 values ('aaa', 'bb1'), ('aaa', 'bb2');

select t1.c1 as c2 from t1, t2 where t1.c2 = t2.c4

group by c2;

c2

aaa

aaa

Warnings:

Warning	1052	Column 'c2' in group statement is ambiguous

show warnings;

Level	Code	Message

Warning	1052	Column 'c2' in group statement is ambiguous

select t1.c1 as c2 from t1, t2 where t1.c2 = t2.c4

group by t1.c1;

c2

aaa

show warnings;

Level	Code	Message

drop table t1, t2;

mysql-test/r/having.result

+1 −0
Original line number Diff line number Diff line
@@ -304,6 +304,7 @@ s1 
0

0

Warnings:

Warning	1052	Column 's1' in group statement is ambiguous

Warning	1052	Column 's1' in having clause is ambiguous

select s1*0 from t1 group by s1 having s1 = 0;

s1*0

mysql-test/t/group_by.test

+23 −0
Original line number Diff line number Diff line
@@ -539,3 +539,26 @@ SELECT hostname, COUNT(DISTINCT user_id) as no FROM t1 
  WHERE hostname LIKE '%aol%'

    GROUP BY hostname;



#

# Bug#11211: Ambiguous column reference in GROUP BY.

#



drop table if exists t1, t2;

create table t1 (c1 char(3), c2 char(3));

create table t2 (c3 char(3), c4 char(3));

insert into t1 values ('aaa', 'bb1'), ('aaa', 'bb2');

insert into t2 values ('aaa', 'bb1'), ('aaa', 'bb2');



# query with ambiguous column reference 'c2'

select t1.c1 as c2 from t1, t2 where t1.c2 = t2.c4

group by c2;



show warnings;



# this query has no ambiguity

select t1.c1 as c2 from t1, t2 where t1.c2 = t2.c4

group by t1.c1;



show warnings;



drop table t1, t2;