Error ORA-00979: not a GROUP BY expression

Question

I have to run a query to list the Product_code, stock_level, and the total quantity ordered
The tables are as follows:
PRODUCT:
PRODUCTCODE     PRODDESCRIPTION     PRICE     STOCKLEVEL
p1      carpet     40     10000
p2      tile     20     100000
p3      pergo     50     50000
PRODLINE:
ORDERNUMBER     PRODCODE     QUANTITY
o1      p1      1000
o1      p2      500
o2      p3      200
o3      p1      600
o3      p3      100
o4      p2      1000
o5      p2      800
Here is my SQL Statement:
SELECT pl.PRODCODE, SUM(pl.QUANTITY), pr.STOCKLEVEL
FROM PRODLINE pl, PRODUCT pr
WHERE pl.PRODCODE=pr.PRODUCTCODE
GROUP BY pl.PRODCODE;
RESULT:
ORA-00979: not a GROUP BY expression
Can someone please assist?

Answer 1

Welconme to the forum!
895231 wrote:
... Here is my SQL Statement:
SELECT pl.PRODCODE, SUM(pl.QUANTITY), pr.STOCKLEVEL
FROM PRODLINE pl, PRODUCT pr
WHERE pl.PRODCODE=pr.PRODUCTCODE
GROUP BY pl.PRODCODE;
RESULT:
ORA-00979: not a GROUP BY expression
Can someone please assist?Remember the ABC's of GROUP BY:
When you use a GROUP BY clause and/or an aggregate fucntion, then everything in the SELECT clause must be:
(A) an <b>A</b>ggregate function,
(B) one of the "group <b>B</b>y" expressions,
(C) a <b>C</b>onstant, or
(D) something that <b>D</b>epends entirely on the above. (For example, if you "GROUP BY TRUNC(dt)", you can SELECT "TO_CHAR (TRUNC(dt), 'Mon-DD')").
In your query, pr.stocklevel is none of the above.
The previous respondent show how you can make it one of the "group <b>B</b>y" expressions, which is noramlly how you would handle this situation.
Alternatively, you could make it an <b>A</b>ggregate function, like this:
SELECT       pl.PRODCODE
,       SUM (pl.QUANTITY)     AS total_quantity
,       MIN (pr.STOCKLEVEL)     AS stokclevel
FROM        PRODLINE      pl
,        PRODUCT      pr
WHERE       pl.PRODCODE     = pr.PRODUCTCODE
GROUP BY  pl.PRODCODE;