-- 更新ID为31的客户的电话号码
UPDATE customers SET T_phone = '13700137000' WHERE T_id = 31;

-- 将所有女性客户的性别更改为“女”
UPDATE customers SET T_rsex = '女' WHERE T_rsex = 'F';
-- 更新ID为002的菜单项的价格
UPDATE menu_items SET M_price = 15.00 WHERE M_id = '002';

-- 将所有素食类菜品的价格降低10%
UPDATE menu_items SET M_price = M_price * 0.9 WHERE M_class = '素';
-- 更新ID为002的折扣规则
UPDATE discount_rules SET discount = 0.75 WHERE M_id = '002';

-- 将所有折扣规则的折扣提高到0.9
UPDATE discount_rules SET discount = 0.9;
-- 更新ID为TABLE07的餐桌状态
UPDATE tables SET Cz_zt = '占用' WHERE Cz_id = 'TABLE07';

-- 将所有编号大于5的餐桌状态更改为“空闲”
UPDATE tables SET Cz_zt = '空闲' WHERE Cz_number > 5;
-- 更新ID为02的员工工资
UPDATE workers SET W_salary = 5200 WHERE W_id = '02';

-- 将所有女性员工的工资提高10%
UPDATE workers SET W_salary = W_salary * 1.1 WHERE W_sex = '女';
-- 更新ID为28的订单时间
UPDATE orders SET time = '2024-12-28 22:19:10' WHERE O_id = 28;

-- 将所有服务员为03的订单的服务员更改为04
UPDATE orders SET W_id = '04' WHERE W_id = '03';
-- 更新ID为21的账单金额
UPDATE bills SET S_price = 35.00, S_priceafter = 31.50 WHERE B_id = 21;

-- 将所有原价大于30的账单的折后价格减少10%
UPDATE bills SET S_priceafter = S_priceafter * 0.9 WHERE S_price > 30;
