Question

我有这个代码工作：

SELECT TOP 1 COUNT(*) AS NumSold, Game.Title
FROM Game JOIN Purchase ON Game.GameID = Purchase.GameID
GROUP BY Game.Title
ORDER BY NumSold DESC ;

我想将顶行的GameID保存为变量。

我试过这个，但似乎无法获得最多'购买'行的'游戏'的游戏ID。当我在绝望中切换变量时，我可以获得各种游戏的购买行数。

SET @BestSellerID = (SELECT TOP 1 COUNT(Game.GameID) AS Best
                     FROM Game JOIN Purchase ON Game.GameID = Purchase.GameID
                     ORDER BY Best DESC
                     );

我也尝试了SELECT方式（INCORRECT SYNTAX NEAR TOP）：

DECLARE @BestSellerID int;

SELECT @BestSellerID = TOP 1 COUNT(Game.GameID) AS NumSold, Game.Title
FROM Game JOIN Purchase ON Game.GameID = Purchase.GameID
GROUP BY Game.Title
ORDER BY NumSold DESC ;

这是不可能的，因为没有办法得到标量结果？有人可以向我解释如何从结果集中获取变量吗？是否有一些我遗漏的概念，是否有一种特殊的方式可以在查询后与“查询”查询？谢谢。

确定用户tshoemake的帮助和摸索语法这解决了我的问题：

    DECLARE @BestSellerID int;

with cte_bs as 
(
SELECT TOP 1 COUNT(Game.GameID) AS NumSold, Game.GameID
FROM Game JOIN Purchase ON Game.GameID = Purchase.GameID
GROUP BY Game.GameID
ORDER BY NumSold DESC
)
select @BestSellerID = (SELECT cte_bs.GameID FROM cte_bs)
select @BestSellerID AS BestSellerGameID;

Answer 1

我看到你正在选择两个元素（GameID和Title）。我想它只在寻找一个存储在局部变量中的GameID。这是在没有样本数据的情况下在黑暗中拍摄的总镜头，但请尝试使用它或使用它来到达您需要的位置。

DECLARE @BestSellerID int;

with cte as 
(
SELECT TOP 1 COUNT(Game.GameID) AS NumSold, Game.GameID
FROM Game JOIN Purchase ON Game.GameID = Purchase.GameID
GROUP BY Game.GameID
ORDER BY NumSold DESC
)
set @BestSellerID = select top 1 cte.GameID from cte 

select @BestSellerID

Answer 2

您可以使用ResultQuery将其存储到java中的本地变量，并使用Mysql数据库

我的代码建议是：

 ResultSet rs=st.executeQuery("SELECT TOP 1 COUNT(*) AS NumSold, Game.Title,Game.GameID
    FROM Game JOIN Purchase ON Game.GameID = Purchase.GameID
    GROUP BY Game.Title
    ORDER BY NumSold DESC ;");
    if(rs.next())
    int GameID=rs.getInt("Game.GameID");

//You can use a array if you want to store large set of numbers

如何在结果集中将局部变量设置为特定值？

2 个答案: