ORA-02070 database does not support semi join in this context

Question

The following merge sql on Oracle 11g throws "ORA-02070 database does not support semi join in this context".
MERGE INTO ORDERS tgt
USING
SELECT C.short_name, C.customer_id
FROM customers C
WHERE customer_id IN ( SELECT distinct customer id FROM orders O WHERE O.order_date > SYSDATE - 3 )
)src
ON ( tgt.customer_id=src.customer_id )
WHEN MATCHED THEN
UPDATE SET tgt.short_name=src.short_name;
Any ideas? This piece of code was working on an earlier version of Oracle 11g.
Thanks,
Anu

Answer 1

Hi, Anu,
You can try this:
MERGE INTO ORDERS     tgt
USING
        SELECT  C.short_name, C.customer_id
     FROM      customers C
)                src
ON (     tgt.customer_id = src.customer_id
   AND     tgt.order_date     > SYSDATE - 3
WHEN MATCHED THEN
     UPDATE  SET     tgt.short_name = src.short_name; It's surprising that the error message mentioned a semi-join, because you weren't doing a semi-join. An example of a semi-join is:
MERGE INTO ORDERS     tgt
USING
        SELECT DISTINCT
               C.short_name, C.customer_id
     FROM        customers C
     JOIN       orders    o     ON  c.customer_id  = o.customer_id
     WHERE       o.order_date     > SYSDATE - 3
)                src
ON (tgt.customer_id = src.customer_id)
WHEN MATCHED THEN
     UPDATE  SET     tgt.short_name = src.short_name; but perhaps the optimizer re-wrote your IN sub-query as a semi-join.
An EXISTS sub-query is another way to get the results you want, unless it causes ORA-02070, also. Natrually, I can't test anythihng, since you didn't post any sample data.
Edited by: Frank Kulash on Apr 5, 2011 11:34 AM