动态IN与SQL

Question

我有两个存储过程，当前选择从Users (U)其中U有一个预订匹配一些条件（IsPaid = 1和MonthNo匹配传递给存储过程）。

--users（U） -

UserID  Name 
1   John 
2   Bill 
3   Tom 

--Bookings（B） -

BookingID  UserID   MonthNo  IsPaid 
5    1    2   1 
6    1    3   1 
7    1    4   0 
8    2    2   1 
9    2    3   1 
10    2    4   1 
11    3    4   1 

ALTER PROCEDURE FindUsers... 
    @MonthNo 
AS 
    ... 
    WHERE B.IsPaid = 1 AND B.MonthNo = @MonthNo 

所以目前，如果@MonthId = 3，用户＃2和＃3返回

我现在需要通过一个列表过程来返回用户的预订范围匹配。即：

ALTER PROCEDURE FindUsers... 
    @MonthNosCsv 
AS 
    ... 
    -- split month numbers somehow, then check whether all matching `Booking` rows match. 

伪代码....

WHERE ALL(B.IsPaid = 1 AND B.MonthNo IN(CsvSplit(@MonthNoCsv))) 

所以，如果@MonthNoCsv是 '2,3,4'，只有用户2返回，因为他们已经在2,3个月内支付预订和4.

这可能在SQL中，还是最好在消费应用程序中进行二次处理？

Answer 1

每个人都应该有一个好的分离器。有很多选项可用。然而，我确实提供了我使用的那个。

下面列出两个选项，第一个是内嵌版本，第二个使用解析函数。两者都会返回相同的结果。

选项1 - 如果没有一个解析函数

Declare @MonthNoCsv varchar(50) = '2,3,4' 

;with cte as (
    Select RetSeq = Row_Number() over (Order By (Select null)) 
      ,RetVal = LTrim(RTrim(B.i.value('(./text())[1]', 'varchar(max)'))) 
    From (Select x = Cast('<x>' + replace((Select replace(@MonthNoCsv,',','§§Split§§') as [*] For XML Path('')),'§§Split§§','</x><x>')+'</x>' as xml).query('.')) as A 
    Cross Apply x.nodes('x') AS B(i) 
) 
Select U.* 
from cte M 
Join Bookings B on M.RetVal=B.MonthNo and B.IsPaid=1 
Join Users U on U.UserID=B.UserID 
Group By U.UserID,U.Name 
Having Count(Distinct B.MonthNo)=(Select max(RetSeq) from cte) 

选项2 - 对于parse函数

Declare @MonthNoCsv varchar(50) = '2,3,4' 
;with cte as (
    Select * from [dbo].[udf-Str-Parse](@MonthNoCsv,',') 
) 
Select U.* 
from cte M 
Join Bookings B on M.RetVal=B.MonthNo and B.IsPaid=1 
Join Users U on U.UserID=B.UserID 
Group By U.UserID,U.Name 
Having Count(Distinct B.MonthNo)=(Select max(RetSeq) from cte) 

都返回

UserID Name 
2  Bill 

的UDF如果有兴趣

CREATE FUNCTION [dbo].[udf-Str-Parse] (@String varchar(max),@Delimiter varchar(10)) 
Returns Table 
As 
Return ( 
    Select RetSeq = Row_Number() over (Order By (Select null)) 
      ,RetVal = LTrim(RTrim(B.i.value('(./text())[1]', 'varchar(max)'))) 
    From (Select x = Cast('<x>' + replace((Select replace(@String,@Delimiter,'§§Split§§') as [*] For XML Path('')),'§§Split§§','</x><x>')+'</x>' as xml).query('.')) as A 
    Cross Apply x.nodes('x') AS B(i) 
); 
--Thanks Shnugo for making this XML safe 
--Select * from [dbo].[udf-Str-Parse]('Dog,Cat,House,Car',',') 
--Select * from [dbo].[udf-Str-Parse]('John Cappelletti was here',' ') 
--Select * from [dbo].[udf-Str-Parse]('this,is,<test>,for,< & >',',')