update语句条件判断更新

UPDATE 
    cw_party tp,cw_shop ts
SET 
    tp.state = 3,
    ts.bonus_average = CASE WHEN ts.bonus_average > 0 THEN (50 + ts.bonus_average) / 2 ELSE 50 END,
    tp.update_time = 1510629839,
    ts.update_time = 1510629839
WHERE
    tp.id = 470
    AND ts.id = 49