為財務部門的僱員加薪,5年以下加5%,5年以上加3%

UPDATE employee e,
 (
#篩選出財務部的員工資訊，並作為臨時表
	SELECT
		e.empid,
		e.sal,
		w.worktime
	FROM
		employee e,
		`work` w
	WHERE
		e.empid = w.empid
	AND w.deptno = (
#選出財務部的編號
		SELECT
			d.deptno
		FROM
			department d
		WHERE
			d.dname = '財務'
	)
) tp#臨時表別名 tp
#使用CASE WHEN對資訊批量修改
SET e.sal = CASE
WHEN tp.worktime >= 5 THEN
	e.sal * (1 + 0.05)
WHEN tp.worktime < 5 THEN
	e.sal * (1 + 0.03)
END
#修改時滿足的條件
WHERE
	e.empid = tp.empid;