CREATE TABLE dept (
deptno NUMERIC(5) NOT NULL,
deptname VARCHAR(20),
location VARCHAR(50)
);
CREATE OR REPLACE TRIGGER auto_increment_deptno
BEFORE INSERT ON dept
FOR EACH ROW
BEGIN
IF :NEW.deptno IS NULL THEN
SELECT COALESCE(MAX(deptno), 0) + 1 INTO :NEW.deptno FROM dept