Question

我创建了一个存储过程，该存储过程从多个选择查询返回记录。

请参阅以下查询：

DECLARE @UserId UNIQUEIDENTIFIER = '96105876-AB55-4D28-A8DD-6BFEC9D38EF8'

SELECT 
    CD.[Name],
    CD.[ASIN],
    CD.[Category],
    CD.[Quantity],
    CD.[Total],
    CD.[Weight]
FROM CartDetails CD
INNER JOIN Cart C ON C.Id = CD.CartId 
INNER JOIN Users U ON U.Id = C.UserId
WHERE U.Id = @UserId AND U.Active = 1 AND U.Deleted = 0

SELECT  
    DCC.DiscountAmount, 
    DCC.DiscountCouponId
FROM DiscountCouponConsumed DCC
INNER JOIN Users U ON U.Id = DCC.UserId
WHERE U.Id = @UserId AND U.Active = 1 AND U.Deleted = 0

在这里，我在where条件中编写了相同的查询（始终保持相同）。现在我的问题是，我们可以一次编写一次where查询并将其用于每个select语句吗？

Answer 1

您可以将有效的用户ID存储在临时表中，该表根据您的常见where子句填充。您可以将这种方法扩展到任意多个查询。

DECLARE @UserId UNIQUEIDENTIFIER = '96105876-AB55-4D28-A8DD-6BFEC9D38EF8';

declare @User table (id uniqueidentifier);

insert into @User (id)
  select id
  from Users U
  where U.Id = @UserId AND U.Active = 1 AND U.Deleted = 0;

SELECT 
    CD.[Name],
    CD.[ASIN],
    CD.[Category],
    CD.[Quantity],
    CD.[Total],
    CD.[Weight]
FROM CartDetails CD
INNER JOIN Cart C ON C.Id = CD.CartId 
INNER JOIN Users U ON U.Id = C.UserId
--WHERE U.Id = @UserId AND U.Active = 1 AND U.Deleted = 0
where U.id in (select id from @User);

SELECT  
  DCC.DiscountAmount,
  DCC.DiscountCouponId
FROM DiscountCouponConsumed DCC
INNER JOIN Users U ON U.Id = DCC.UserId
--WHERE U.Id = @UserId AND U.Active = 1 AND U.Deleted = 0
where U.id in (select id from @User);

Answer 2

如果您有单独的select语句，它们之间没有任何关系，那么这可能会对您有所帮助。在执行选择查询之前，在单独的变量中准备选择查询和Where查询，并将它们连接在一起。

DECLARE @UserId UNIQUEIDENTIFIER = '96105876-AB55-4D28-A8DD-6BFEC9D38EF8'

DECLARE @Query NVARCHAR(MAX) , @SelectQuery NVARCHAR(MAX), @WhereQuery NVARCHAR(MAX)

SET @WhereQuery = 'WHERE U.Id = @UserId AND U.Active = 1 AND U.Deleted = 0'

 -- Query 1 

SET @SelectQuery =
'SELECT 
    CD.[Name],
    CD.[ASIN],
    CD.[Category],
    CD.[Quantity],
    CD.[Total],
    CD.[Weight]
FROM CartDetails CD
INNER JOIN Cart C ON C.Id = CD.CartId 
INNER JOIN Users U ON U.Id = C.UserId'

SET @Query = @SelectQuery + @WhereQuery

EXEC (@Query)


--- Query 2

SET @Query = NULL 

SET @SelectQuery = NULL

SET @SelectQuery ='
SELECT  
    DCC.DiscountAmount, 
    DCC.DiscountCouponId
FROM DiscountCouponConsumed DCC
INNER JOIN Users U ON U.Id = DCC.UserId '

SET @Query = @SelectQuery + @WhereQuery

EXEC (@Query)

Answer 3

接近Dales答案，但加入@Users。

DECLARE @UserId UNIQUEIDENTIFIER = '96105876-AB55-4D28-A8DD-6BFEC9D38EF8';

DECLARE @Users TABLE
(
    Id INT,
    Active BIT,
    Deleted BIT
);

INSERT INTO @Users
(
    Id,
    Active,
    Deleted
)
SELECT Id,
       Active,
       Deleted
FROM Users
WHERE U.Id = @UserId
      AND U.Active = 1
      AND U.Deleted = 0;

SELECT CD.Name,
       CD.ASIN,
       CD.Category,
       CD.Quantity,
       CD.Total,
       CD.Weight
FROM CartDetails CD
    INNER JOIN Cart C
        ON C.Id = CD.CartId
    INNER JOIN @Users U
        ON U.Id = C.UserId;

SELECT DCC.DiscountAmount,
       DCC.DiscountCouponId
FROM DiscountCouponConsumed DCC
    INNER JOIN @Users U
        ON U.Id = DCC.UserId;

Answer 4

@MarcinJ在评论中提供了最简单的答案，我认为值得回答。

如果您始终以这种方式过滤用户记录，只需运行查询检查用户是否处于活动状态并且在开始时未将其删除您的存储过程，如果不符合您的条件，请重置 @UserId设置为NULL，以便其他任何查询都不会产生结果

即在proc的顶部具有以下代码：

select @UserId = case when exists (
    select 1
    from Users U
    where U.Id = @UserId AND U.Active = 1 AND U.Deleted = 0
  ) then @UserId else null end;

在整个存储过程中重用条件？

4 个答案: