Not a GROUP BY expression - Oracle 10g bug?

Question

Hi,
I am geting 00979. 00000 - "not a GROUP BY expression" error on Oracle 10g 10.2.0.4.0 - 64bit Production.
To illustrate my problem I created following example.
Let think I have some shop with clothes. Everytime I sell something, I store this information in the database - storing actual time, clothes type (trousers, socks, ...) and the size of the piece (M, L, XL, ...).
Now, system counts statistics every hour. So it goes thrue the table with sold pieces and counts the number of pieces per clothes type and per size from the beginning of the day. It is important to realize that it is from the beginning of the day. Because of that, the number of sold pieces in the statistical table grows every hour (or is at least on the same value as in previous hour).
Now, from this statistical table I need to make new statistic. I want a statistic how many pieces per size I sold every hour.
I created this query for that:
SELECT TIME, xSIZE, (SOLD  - NVL((SELECT SUM(S1.SOLD)
                                  FROM STATISTICS S1
                                  WHERE S1.xSIZE = S.xSIZE
                                    AND TRUNC(S1.TIME, 'HH24') + 1/24 = S.TIME
                                    AND TO_CHAR(S1.TIME, 'HH24') != '23'
                                    AND S1.xSIZE IS NOT NULL
                                  GROUP BY TRUNC(S1.TIME, 'HH24'), S1.xSIZE),0)) SOLD
FROM(
SELECT TRUNC(S.TIME, 'HH24') TIME, S.xSIZE, SUM(S.SOLD) SOLD
FROM STATISTICS S
WHERE S.xSIZE IS NOT NULL
GROUP BY TRUNC(S.TIME, 'HH24'), S.xSIZE
--ORDER BY 1 DESC
) S
ORDER BY TIME DESC, xSIZE ASCFirst I select number of sold pieces per hour per size. To get number of sold pieces for particular hour, I need to substract from this value number of sold pieces from previous hour. I decided to do this with parameter query...
Running the query like this I get "not a GROUP BY expression" error. However if I uncomment the "ORDER BY 1 DESC" statement, the query works. I am pretty sure it has to do something with this line:
AND TRUNC(S1.TIME, 'HH24') + 1/24 = S.TIME
If you modify this query like this:
SELECT TIME, xSIZE, (SOLD  - NVL((SELECT SUM(S1.SOLD)
                                  FROM STATISTICS S1
                                  WHERE S1.xSIZE = S.xSIZE
                                    --AND TRUNC(S1.TIME, 'HH24') + 1/24 = S.TIME
                                    AND TO_CHAR(S1.TIME, 'HH24') != '23'
                                    AND S1.xSIZE IS NOT NULL
                                  GROUP BY  S1.xSIZE),0)) SOLD
FROM(
SELECT TRUNC(S.TIME, 'HH24') TIME, S.xSIZE, SUM(S.SOLD) SOLD
FROM STATISTICS S
WHERE S.xSIZE IS NOT NULL
GROUP BY TRUNC(S.TIME, 'HH24'), S.xSIZE
--ORDER BY 1 DESC
) S
ORDER BY TIME DESC, xSIZE ASCRemoved joining the tables on truncated time and grouping by the truncated time -> The query does not fail...
And now the best...if you run the first query on Oracle 11g (Release 11.1.0.6.0 - 64bit Production), it works.
Does anybody know why is the first query not working on 10g? Is there some bug or limitation for this server version?
Please don't say me to rewrite the query in another way, I already did it, so it works on 10g as well. I am just curious why it doesn't work on 10g.
Finally here are some data for testing.
CREATE TABLE STATISTICS(
  TIME DATE DEFAULT SYSDATE,
  TYPE VARCHAR2(20),
  xSIZE VARCHAR2(2),
  SOLD NUMBER(5,0) DEFAULT 0
INSERT INTO STATISTICS(TIME, TYPE, xSIZE, SOLD) VALUES(SYSDATE - 2/24, 'T-Shirt', 'M', 10);
INSERT INTO STATISTICS(TIME, TYPE, xSIZE, SOLD) VALUES(SYSDATE - 2/24, 'Socks', 'M', 3);
INSERT INTO STATISTICS(TIME, TYPE, xSIZE, SOLD) VALUES(SYSDATE - 2/24, 'T-Shirt', 'L', 1);
INSERT INTO STATISTICS(TIME, TYPE, xSIZE, SOLD) VALUES(SYSDATE - 2/24, 'Socks', 'L', 50);
INSERT INTO STATISTICS(TIME, TYPE, xSIZE, SOLD) VALUES(SYSDATE - 2/24, 'Trousers', 'XL', 7);
INSERT INTO STATISTICS(TIME, TYPE, xSIZE, SOLD) VALUES(SYSDATE - 2/24, 'Socks', 'XL', 3);
INSERT INTO STATISTICS(TIME, TYPE, xSIZE, SOLD) VALUES(SYSDATE - 1/24, 'T-Shirt', 'M', 13);
INSERT INTO STATISTICS(TIME, TYPE, xSIZE, SOLD) VALUES(SYSDATE - 1/24, 'Socks', 'L', 60);
INSERT INTO STATISTICS(TIME, TYPE, xSIZE, SOLD) VALUES(SYSDATE - 1/24, 'Trousers', 'XL', 15);
INSERT INTO STATISTICS(TIME, TYPE, xSIZE, SOLD) VALUES(SYSDATE - 1/24, 'Socks', 'XL', 6);Edited by: user12047225 on 20.9.2011 23:12
Edited by: user12047225 on 20.9.2011 23:45

Answer 1

It is a known issue when optimizer decides to expand in-line view. You can add something (besides ORDER BY you already used) to in-line view to prevent optimizer from expanding it. For example:
SQL> SELECT  TIME,
  2          xSIZE,
  3          (SOLD - NVL(
  4                      (
  5                       SELECT  SUM(S1.SOLD)
  6                         FROM  STATISTICS S1
  7                         WHERE S1.xSIZE = S.xSIZE
  8                           AND TRUNC(S1.TIME, 'HH24') + 1/24 = S.TIME
  9                           AND TO_CHAR(S1.TIME, 'HH24') != '23'
10                           AND S1.xSIZE IS NOT NULL
11                           GROUP BY TRUNC(S1.TIME, 'HH24'),
12                                    S1.xSIZE
13                      ),
14                      0
15                     )
16          ) SOLD
17    FROM  (
18           SELECT  TRUNC(S.TIME, 'HH24') TIME,
19                   S.xSIZE,
20                   SUM(S.SOLD) SOLD
21             FROM  STATISTICS S
22             WHERE S.xSIZE IS NOT NULL
23             GROUP BY TRUNC(S.TIME, 'HH24'),
24                      S.xSIZE
25           --ORDER BY 1 DESC
26          ) S
27    ORDER BY TIME DESC,
28             xSIZE ASC
29  /
         SELECT  TRUNC(S.TIME, 'HH24') TIME,
ERROR at line 18:
ORA-00979: not a GROUP BY expression
SQL> SELECT  TIME,
  2          xSIZE,
  3          (SOLD - NVL(
  4                      (
  5                       SELECT  SUM(S1.SOLD)
  6                         FROM  STATISTICS S1
  7                         WHERE S1.xSIZE = S.xSIZE
  8                           AND TRUNC(S1.TIME, 'HH24') + 1/24 = S.TIME
  9                           AND TO_CHAR(S1.TIME, 'HH24') != '23'
10                           AND S1.xSIZE IS NOT NULL
11                           GROUP BY TRUNC(S1.TIME, 'HH24'),
12                                    S1.xSIZE
13                      ),
14                      0
15                     )
16          ) SOLD
17    FROM  (
18           SELECT  TRUNC(S.TIME, 'HH24') TIME,
19                   S.xSIZE,
20                   SUM(S.SOLD) SOLD,
21                   ROW_NUMBER() OVER(ORDER BY SUM(S.SOLD)) RN
22             FROM  STATISTICS S
23             WHERE S.xSIZE IS NOT NULL
24             GROUP BY TRUNC(S.TIME, 'HH24'),
25                      S.xSIZE
26           --ORDER BY 1 DESC
27          ) S
28    ORDER BY TIME DESC,
29             xSIZE ASC
30  /
TIME      XS       SOLD
20-SEP-11 L           9
20-SEP-11 M           0
20-SEP-11 XL         11
20-SEP-11 L          51
20-SEP-11 M          13
20-SEP-11 XL         10
6 rows selected.
SQL> Or use subquery factoring (WITH clause) + undocumented hint MATERIALIZE:
SQL> WITH S AS (
  2             SELECT  /*+ MATERIALIZE */ TRUNC(S.TIME, 'HH24') TIME,
  3                     S.xSIZE,
  4                     SUM(S.SOLD) SOLD
  5               FROM  STATISTICS S
  6               WHERE S.xSIZE IS NOT NULL
  7               GROUP BY TRUNC(S.TIME, 'HH24'),
  8                        S.xSIZE
  9             --ORDER BY 1 DESC
10            )
11  SELECT  TIME,
12          xSIZE,
13          (SOLD - NVL(
14                      (
15                       SELECT  SUM(S1.SOLD)
16                         FROM  STATISTICS S1
17                         WHERE S1.xSIZE = S.xSIZE
18                           AND TRUNC(S1.TIME, 'HH24') + 1/24 = S.TIME
19                           AND TO_CHAR(S1.TIME, 'HH24') != '23'
20                           AND S1.xSIZE IS NOT NULL
21                           GROUP BY TRUNC(S1.TIME, 'HH24'),
22                                    S1.xSIZE
23                      ),
24                      0
25                     )
26          ) SOLD
27    FROM  S
28    ORDER BY TIME DESC,
29             xSIZE ASC
30  /
TIME      XS       SOLD
20-SEP-11 L           9
20-SEP-11 M           0
20-SEP-11 XL         11
20-SEP-11 L          51
20-SEP-11 M          13
20-SEP-11 XL         10
6 rows selected.
SQL> SY.