Need help with the query -

Question

We have these two tables and trying to see if the amount in one table is equal to the sum of the amount fields in another table.
Can someone please help?
SQL> desc test;
Name Null? Type
KEY NUMBER(9)
AMOUNT NUMBER(11,2)
SQL> desc test1;
Name Null? Type
KEY NUMBER(9)
TOTAL_AMOUNT NUMBER(11,2)
SQL> select * from test;
KEY AMOUNT
1 10
1 20
1 70
3 rows selected.
SQL> select * from test1;
KEY TOTAL_AMOUNT
1 100
1 row selected.
SQL> select count(*) from test1 a where exists(select 'x' from test b where
2 a.key=b.key and a.total_amount!=sum(b.amount));
a.key=b.key and a.total_amount!=sum(b.amount))
ERROR at line 2:
ORA-00934: group function is not allowed here

Answer 1

Hi,
This would be so easy if there was a table like test that only had one row per key!
You can make such a table, or you can just make a sub-query that has all the same data, and use that sub-query as if it were a table.
For example:
WITH  one_row_per_key_test  AS
    SELECT    key
    ,         SUM (amount)  AS total_amount
    FROM      test
    GROUP BY  key
SELECT  COUNT (*)
FROM    test1   a
WHERE   EXISTS
        SELECT  'x'
        FROM    one_row_per_key_test  b
        WHERE   a.key          = b.key
        AND     a.total_amount = b.total_amount
        );There are lots of other ways to solve this particular problem (including HAVING), but this is a very important technique to know.