Question

I have to insert/update some RECORDS in table target_table. These records are coming one source_table.

I am using MERGE for update/insert the target_table.

MERGE
   INTO  target_table tgt
   USING source_table src
   ON  ( src.column1 = tgt.column1 and
         src.column2 = tgt.column2)
WHEN MATCHED
THEN
   UPDATE
   SET   tgt.column3= src.column3,
         tgt.column4 = src.coulmn4   
WHEN NOT MATCHED
   THEN
INSERT ( tgt.column1,
         tgt.column2,
         tgt.column3,
         tgt.column4 )
VALUES ( src.coulmn1,
         src.coulmn2,
         src.coulmn3,
         src.coulmn4);

I want to add some specific condition on update.

IF target_table.column3 in (val1','val2)

then only there should be update, else no update or insert.

Answer 1

You can simply add WHERE clause to UPDATE. More about it in oracle docs.

So in your case it should look like:

...
WHEN MATCHED
THEN
   UPDATE
   SET   tgt.column3= src.column3,
         tgt.column4 = src.coulmn4
   WHERE tgt.column3 IN (val1, val2) 
WHEN NOT MATCHED
...