gistfile1.txt

IF (NOT EXISTS(SELECT * FROM QSYS2.SYSTABLES WHERE TABLE_SCHEMA = 'BACKUP' AND TABLE_NAME='MYTABLE')) THEN
    CREATE TABLE BACKUP.MYTABLE 
    AS (SELECT * FROM MYLIB.MYTABLE)
    WITH DATA;
ELSE
    INSERT INTO BACKUP.MYTABLE 
        SELECT * FROM MYLIB.MYTABLE;
END IF;