動態IN與SQL

Question

我有兩個存儲過程，當前選擇從Users (U)其中U有一個預訂匹配一些條件（IsPaid = 1和MonthNo匹配傳遞給存儲過程）。

--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，用戶＃2和＃3返回

我現在需要通過一個列表過程來返回用戶的預訂範圍匹配。即：

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

僞代碼....

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

所以，如果@MonthNoCsv是 '2,3,4'，只有用戶2返回，因爲他們已經在2,3個月內支付預訂和4.

這可能在SQL中，還是最好在消費應用程序中進行二次處理？

Answer 1

每個人都應該有一個好的分離器。有很多選項可用。然而，我確實提供了我使用的那個。

下面列出兩個選項，第一個是內嵌版本，第二個使用解析函數。兩者都會返回相同的結果。

選項1 - 如果沒有一個解析函數

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) 

選項2 - 對於parse函數

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如果有興趣

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,< & >',',')