Sql server 2008 在SQL Server WHERE子句中使用CASE语句

我试图根据每个州或城市的人口数量来更改

WHERE

子句

如果一个州有超过10人，我希望

的位置是：

WHERE u.StateID = @StateID 

如果一个城市的人口超过10人，我希望是：

WHERE u.CityID = @CityID 

WHERE u.CountryID = '1'



ALTER PROCEDURE GetHighscore
(@UserID int)
AS
BEGIN
Declare @StateCount int
Declare @CityCount int
Declare @StateID int
Declare @CityID int

SELECT @StateID=StateID FROM tblUser WHERE UserID = @UserID

SELECT @CityID=CityID FROM tblUser WHERE UserID = @UserID

SELECT  @StateCount=COUNT(DISTINCT tblUserTrix.UserID)
FROM            tblUserTrix INNER JOIN
                         tblUser ON tblUserTrix.UserID = tblUser.UserID
WHERE        (tblUser.StateID = @StateID)

SELECT @CityCount=COUNT(DISTINCT tblUserTrix.UserID)
FROM            tblUserTrix INNER JOIN
                         tblUser ON tblUserTrix.UserID = tblUser.UserID
WHERE        (tblUser.CityID = @CityID)


SELECT TOP 10        ut.UserID, SUM(t.Hardness) AS TotalTrixPoints, u.FirstName, u.LastName, u.StateID, u.CityID, tblSweCitys.CityName
FROM            tblUserTrix AS ut INNER JOIN
                         tblUser AS u ON ut.UserID = u.UserID INNER JOIN
                         tblState ON u.StateID = tblState.StateID INNER JOIN
                         tblCitys ON u.CityID = tblCitys.CityID LEFT OUTER JOIN
                         tblTrix AS t ON ut.TrixID = t.TrixID

WHERE CASE 
WHEN @StateCount > 10 
THEN u.StateID = @StateID

WHEN @CityCount > 10 
THEN u.CityID = @CityID
ELSE u.CountryID = '1'
        END = ?

GROUP BY ut.UserID, u.FirstName, u.LastName, u.CityID, u.StateID, tblCitys.CityName
ORDER BY TotalTrixPoints DESC   

END

而不是

WHERE u.StateID = @StateID

如果城市或州的人口不超过10人，我希望是：

WHERE u.CityID = @CityID 

WHERE u.CountryID = '1'



ALTER PROCEDURE GetHighscore
(@UserID int)
AS
BEGIN
Declare @StateCount int
Declare @CityCount int
Declare @StateID int
Declare @CityID int

SELECT @StateID=StateID FROM tblUser WHERE UserID = @UserID

SELECT @CityID=CityID FROM tblUser WHERE UserID = @UserID

SELECT  @StateCount=COUNT(DISTINCT tblUserTrix.UserID)
FROM            tblUserTrix INNER JOIN
                         tblUser ON tblUserTrix.UserID = tblUser.UserID
WHERE        (tblUser.StateID = @StateID)

SELECT @CityCount=COUNT(DISTINCT tblUserTrix.UserID)
FROM            tblUserTrix INNER JOIN
                         tblUser ON tblUserTrix.UserID = tblUser.UserID
WHERE        (tblUser.CityID = @CityID)


SELECT TOP 10        ut.UserID, SUM(t.Hardness) AS TotalTrixPoints, u.FirstName, u.LastName, u.StateID, u.CityID, tblSweCitys.CityName
FROM            tblUserTrix AS ut INNER JOIN
                         tblUser AS u ON ut.UserID = u.UserID INNER JOIN
                         tblState ON u.StateID = tblState.StateID INNER JOIN
                         tblCitys ON u.CityID = tblCitys.CityID LEFT OUTER JOIN
                         tblTrix AS t ON ut.TrixID = t.TrixID

WHERE CASE 
WHEN @StateCount > 10 
THEN u.StateID = @StateID

WHEN @CityCount > 10 
THEN u.CityID = @CityID
ELSE u.CountryID = '1'
        END = ?

GROUP BY ut.UserID, u.FirstName, u.LastName, u.CityID, u.StateID, tblCitys.CityName
ORDER BY TotalTrixPoints DESC   

END

必须使用和/或运算符和嵌套条件，而不是大小写

(@StateCount > 10 AND u.StateID = @StateID) OR (@CityCount > 10 AND CityID = @CityID) OR (CountryID = '1')

有些人喜欢这样

UPDADE：

所以，这个例子对你来说确实不太合适。您需要更复杂的where子句。试试这个：

(@StateCount > 10 AND u.StateID = @StateID)
OR
(@CityCount > 10 AND @StateCount <= 10 AND CityID = @CityID)
OR
(@StateCount <= 10 AND @CityCount <= 10 AND CountryID = '1')

（@StateCount>10和u.StateID=@StateID）
或
（@CityCount>10和@StateCount这听起来真是个糟糕的主意-你必须找出人数（这是英语中“person”的正确复数）首先在一个城市或州，在您决定如何动态构建SQL语句之前……好的，我将试着记住Marc。每个城市或州的人口数量可以从StateCount和CityCount中获得。好的，但是即使一个城市有50人，我也不会得到该城市的高分，因为有or（CountryID='1'）每个人都有countryID 1。正因为如此，我让每个人都在高分，而不仅仅是城市。更新答案。这是完整的指定标准。它可以通过使用嵌套条件进行优化。