Sql server 如何使用where子句将值传递给子查询的日期变量部分
我希望通过where子句控制声明的变量 我有这样一个查询示例:Sql server 如何使用where子句将值传递给子查询的日期变量部分,sql-server,stored-procedures,declare,stored-functions,Sql Server,Stored Procedures,Declare,Stored Functions,我希望通过where子句控制声明的变量 我有这样一个查询示例: DECLARE @dateplaceholder AS DATETIME SET @dateplaceholder = '2019-06-01' SELECT @dateplaceholder PLACEHOLDER_DATE, GETDATE() AS TODAY, SOME_DATE_AGO = (SELECT dateadd(DAY, -7, @dateplaceholder )) GO DECLARE @dateplac
DECLARE @dateplaceholder AS DATETIME
SET @dateplaceholder = '2019-06-01'
SELECT @dateplaceholder PLACEHOLDER_DATE, GETDATE() AS TODAY, SOME_DATE_AGO = (SELECT dateadd(DAY, -7, @dateplaceholder ))
GO
DECLARE @dateplaceholder AS DATETIME
SET @dateplaceholder = '2019-06-01'
SELECT @dateplaceholder PLACEHOLDER_DATE, GETDATE() AS TODAY, SOME_DATE_AGO = (SELECT dateadd(DAY, -7, @dateplaceholder ))
WHERE SELECT @dateplaceholder = '2018-01-01'
GO
CREATE PROCEDURE [usersp_YourQueryName] @dateplaceholder AS datetime
AS
BEGIN
SELECT @dateplaceholder PLACEHOLDER_DATE, GETDATE() AS TODAY, SOME_DATE_AGO = (SELECT dateadd(DAY, -7, @dateplaceholder ))
END
GO
EXEC [usersp_YourQueryName] '2019-06-01'
这将按预期工作。给出以下结果:
现在,我想控制where子句上的@dateplaceholder
变量,以便使我的查询成为一个视图,我可以调用:
选择*myqueryView其中@dateplaceholder='2018-01-01'
大概是这样的:
DECLARE @dateplaceholder AS DATETIME
SET @dateplaceholder = '2019-06-01'
SELECT @dateplaceholder PLACEHOLDER_DATE, GETDATE() AS TODAY, SOME_DATE_AGO = (SELECT dateadd(DAY, -7, @dateplaceholder ))
GO
DECLARE @dateplaceholder AS DATETIME
SET @dateplaceholder = '2019-06-01'
SELECT @dateplaceholder PLACEHOLDER_DATE, GETDATE() AS TODAY, SOME_DATE_AGO = (SELECT dateadd(DAY, -7, @dateplaceholder ))
WHERE SELECT @dateplaceholder = '2018-01-01'
GO
CREATE PROCEDURE [usersp_YourQueryName] @dateplaceholder AS datetime
AS
BEGIN
SELECT @dateplaceholder PLACEHOLDER_DATE, GETDATE() AS TODAY, SOME_DATE_AGO = (SELECT dateadd(DAY, -7, @dateplaceholder ))
END
GO
EXEC [usersp_YourQueryName] '2019-06-01'
但是,它不会返回任何结果,因为它基本上是在检查where子句中声明的变量是否具有该值,它不会设置它
有没有办法解决这个问题?您可以使用表值函数返回所需的数据,然后使用所需的参数值。像这样
CREATE FUNCTION [YourQueryName]
(@dateplaceholder datetime)
RETURNS TABLE
AS
RETURN
SELECT
@dateplaceholder PLACEHOLDER_DATE,
GETDATE() AS TODAY,
SOME_DATE_AGO = (SELECT dateadd(DAY, -7, @dateplaceholder ))
GO
DECLARE @dateplaceholder AS DATETIME
SET @dateplaceholder = '2018-01-01'
select * from [YourQueryName](@dateplaceholder)
如果您愿意,也可以使用如下StoredProcess:
DECLARE @dateplaceholder AS DATETIME
SET @dateplaceholder = '2019-06-01'
SELECT @dateplaceholder PLACEHOLDER_DATE, GETDATE() AS TODAY, SOME_DATE_AGO = (SELECT dateadd(DAY, -7, @dateplaceholder ))
GO
DECLARE @dateplaceholder AS DATETIME
SET @dateplaceholder = '2019-06-01'
SELECT @dateplaceholder PLACEHOLDER_DATE, GETDATE() AS TODAY, SOME_DATE_AGO = (SELECT dateadd(DAY, -7, @dateplaceholder ))
WHERE SELECT @dateplaceholder = '2018-01-01'
GO
CREATE PROCEDURE [usersp_YourQueryName] @dateplaceholder AS datetime
AS
BEGIN
SELECT @dateplaceholder PLACEHOLDER_DATE, GETDATE() AS TODAY, SOME_DATE_AGO = (SELECT dateadd(DAY, -7, @dateplaceholder ))
END
GO
EXEC [usersp_YourQueryName] '2019-06-01'
视图
不能参数化。如果需要引用变量,则需要在视图
之外执行,或者使用可以参数化的不同类型的对象;例如存储过程或内联表值函数。