我尝试添加一个检查约束,但到目前为止我只失败了。有什么方法可以解决这个问题:
消息 1046,第 15 级,状态 1,第 6 行
在此上下文中不允许子查询。仅标量表达式 是允许的。
这是代码:
ALTER TABLE dbo.PropertySeasonDiscount ADD CONSTRAINT
[CC_PropertySeasonDiscount_MadeFrom_MadeTo]
CHECK (
(SELECT COUNT(PropertySeasonDiscountId) FROM dbo.PropertySeasonDiscounts apsdeb
WHERE
(apsdeb.PropertySeasonId = PropertySeasonId) AND
(
(apsdeb.ValidForReservationsMadeTo >= ValidForReservationsMadeFrom AND ValidForReservationsMadeFrom >= apsdeb.ValidForReservationsMadeFrom) OR
(apsdeb.ValidForReservationsMadeFrom <= ValidForReservationsMadeTo AND ValidForReservationsMadeTo <= apsdeb.ValidForReservationsMadeTo)
)
) = 0
);