Question

I use DB2 and writing a trigger count version works but I can’t convert it to exists version. I will use exists version because of performance reasons. It is a insert after trigger.

it works

   IF  (SELECT COUNT(*) FROM table where field=NEW.field ) = 0 THEN
    ---------
   END IF;--

it doesn’t work

   IF NOT EXISTS (SELECT * FROM table where field=NEW.field )  THEN
    ---------------------
    END IF;--

Answer 1

TRY THIS: ,AS

BEGIN ATOMIC
IF NOT EXISTS (SELECT * FROM table where field=NEW.field)
THEN
INSERT INTO ABC.table1 (“field1”) VALUES (1100200); –> HERE IS A DUMMY INSERT I USED TO EXPLAIN
END IF;
END;

this syntax to run this code

db2 -td@ -f mysql.db2

You need to tell DB2 about the terminator you used !!

AND

–#SET TERMINATOR $
This will ser the terminator to $
To change the terminator in the CLP on the fly, the following syntax will set it back:
–#SET TERMINATOR