Question

表：

[dbo].[Dealer]
[number] [firstName] [surName]   [birthDate] [startWorkingDate] [ID]
Num Dealer|full name of Dealers| birthdate | date + time       | id number
[dbo].[Game]

[gameTypeName] [gameStartDateTime] [gameEndTime] [DealerInGame]
name of game  | date + time      | date + time| same numbers like [Dealer].[number]

我想要查询的内容：返回经销商（员工编号和全名）的查询，参与最少量的游戏。

SELECT top 1 number,firstName +' '+ surName as 'full name' FROM Dealer
where  exists (SELECT gameTypeName,COUNT( gameTypeName)  FROM Game 
GROUP BY gameTypeName)

查询只给我带来了第一个游戏数量最少的游戏，但如果有2个或更多经销商具有相同的价值，那么它就不会全部显示。

怎么了？

Answer 1

我不认为，MySQL支持TOP运算符，就像SQL Server一样，但你可以使用LIMIT获得第一条记录，如下所示：

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Answer 2

加入两个表，使用COUNT()，然后使用ORDER BY和LIMIT 1。这是它的MySQL语法：

SELECT number, CONCAT(firstName, ' ', lastName) AS fullName
FROM Dealer AS d
JOIN Game AS g ON g.DealerInGame = d.number
GROUP BY d.number
ORDER BY COUNT(*)
LIMIT 1

Answer 3

您可以执行join：

select d.number, CONCAT(d.firstName, ' ', d.lastName) as fullName
from Dealer d inner join ( 
           select DealerInGame
           from Game
           group by DealerInGame
           having count(*) <= 1
      ) g on g.DealerInGame = d.number;

Answer 4

如果您希望所有经销商拥有最少数量的游戏，您需要参加最少数量的游戏，然后找到所有拥有该游戏数量的经销商。

WITH GameCount as (
    SELECT 
        DealerInGame, 
        Count(*) Games
    FROM Game
    )

SELECT 
    d.firstName + ' ' + d.surName fullName,
    d.number
FROM GameCount g
    LEFT JOIN Dealer d on d.Number = g.DealerInGame
WHERE g.Games = (
    SELECT Min(Games)
    FROM GameCount)

SQL ISSUE-查询计数帮助+分钟

4 个答案: