quote:
As I suspected, tried with spcific columns but still the same error..............
I've had this error before. Specify the columns you want to insert as well as the specific columns you are selecting.
insert into customer(ColA,ColB,ColC)
select A,B,C from clnpers
WHERE NOT EXISTS (
SELECT * FROM customer WHERE
customer.cust_id = clnpers.cust_id
AND customer.rec_fname = clnpers.rec_fname
AND customer.rec_sname = clnpers.rec_sname
AND customer.rec_bday = clnpers.rec_bday)