Query diferent output between 11gR1 and 11gR2

Question

We have a complex query which has been working fine in 11gR1 and after changing aplication to 11gR2 it started generating an error.
This simple table and query shows the same error I am seeing.
In 11gR2 this first select gives an error ORA-00979
In 11gR1 it works fine
Create this table
CREATE TABLE TAB1
+(+
+"PKEY" NUMBER NOT NULL ENABLE,+
+"FKEY1" NUMBER ,+
+"FKEY2" NUMBER,+
CONSTRAINT "TAB1_PK" PRIMARY KEY ("PKEY")  ENABLE
+)+
+;+
THIS SHOWS ERROR
select somenumber
from
+(+
SELECT
+(SELECT 1+
FROM DUAL
WHERE 99999=t1.fkey1
+) somenumber+
FROM tab1 t1
GROUP BY
t1.fkey1,
t1.pkey
+)+
ORA-00979: "not a GROUP BY expression"
Error at Line: 7 Column: 18
THIS WORKS (Substitute t1.pkey in GROUP by with t1.fkey2 - Here we see that error generated above is only generated when GROUP BY is done by primary key when using fkey2 it does not give error)
SELECT somenumber
FROM
+(+
SELECT
+(SELECT 1+
FROM DUAL
WHERE 99999=t1.fkey1
+) somenumber+
FROM tab1 t1
GROUP BY
t1.fkey1,
t1.fkey2
+)+
THIS WORKS (Add [+GROUP BY somenumber+] to end - should not be necessary since no distinct or aggregate function in outer select)
select somenumber
from
+(+
SELECT
+(SELECT 1+
FROM DUAL
WHERE 99999=t1.fkey1
+) somenumber+
FROM tab1 t1
GROUP BY
t1.fkey1,
t1.pkey
+)+
GROUP BY somenumber
Does anyone seen this behavior before?
Alexandre.

Answer 1

Looks like a bug in 11gr2 (i was able to reproduce your results) and tested against an XE instance where the query executes without problem (as in your 11gr1 instance).
Since you have a nice little demonstration set up you should easily be able to file a Metalink (MOS) incident and get Oracle looking at this.
Though for the example you've posted the simple fix would be to make the query less 'weird' :)
drop TABLE TAB1;
CREATE TABLE TAB1
   PKEY NUMBER NOT NULL ENABLE,
   FKEY1 NUMBER ,
   FKEY2 NUMBER
   , CONSTRAINT TAB1_PK PRIMARY KEY (PKEY) ENABLE
insert into tab1 values (1, 99999, 9);
insert into tab1 values (2, 0, 10);
Table dropped.
ME_XE?ME_XE?  2    3    4    5    6    7    8 
Table created.
ME_XE?ME_XE?
1 row created.
ME_XE?
1 row created.
ME_XE?
ME_XE?
ME_XE?
ME_XE?
select somenumber
from
SELECT
(SELECT 1
FROM DUAL
WHERE 99999=t1.fkey1
) somenumber
FROM tab1 t1
GROUP BY
t1.fkey1,
t1.pkey
13  );
SOMENUMBER
      1
2 rows selected.
SELECT
   somenumber
FROM
      SELECT
         case when t1.fkey1 = 99999
         then
            1
         else
            null
         end as somenumber
      FROM
         tab1  t1
      GROUP BY
         t1.fkey1,
         t1.pkey
17     );
SOMENUMBER
      1
2 rows selected.
ME_XE?As i said, i can run this fine on my XE instance so i used that to demonstrate how i would rewrite the query which to me at least makes more sense.
And the run on my 11.2 instance
insert into tab1 values (1, 99999, 9);
insert into tab1 values (2, 0, 10);
1 row created.
TUBBY_TUBBZ?
1 row created.
SELECT
   somenumber
FROM
      SELECT
         case when t1.fkey1 = 99999
         then
            1
         else
            null
         end as somenumber
      FROM
         tab1  t1
      GROUP BY
         t1.fkey1,
         t1.pkey
17     );
SOMENUMBER
      1
2 rows selected.
TUBBY_TUBBZ?select * from v$version;
BANNER
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
PL/SQL Release 11.2.0.1.0 - Production
CORE     11.2.0.1.0     Production
TNS for Linux: Version 11.2.0.1.0 - Production
NLSRTL Version 11.2.0.1.0 - Production
5 rows selected.Edited by: Tubby on Sep 9, 2010 6:40 PM
Added 11.2 test run.