选择条件为真且计数> 3的总和

Question

我有两张桌子。

• FootballPlayers的列Id_footballplayer，姓氏，Fisrt_Name，年龄
• Transfers的列Id_transfer，Name_club，价格，日期，验收（是或否），code_footballplayer

如何编写 SQL 查询来选择玩家的姓氏以及他们进行的成功转会总数超过 3 的总和？

我已经写了一个查询，显示每个玩家所有成功转移的总金额

SELECT FootballPLayers.Last_Name, 
       SUM(CASE acceptance WHEN 'yes' THEN price ELSE 0 END) AS amount_price
FROM  FootballPlayers 
  INNER JOIN Transfers ON FootballPlayers.ID_footballplayer = Transfers.code_footballplayer
GROUP BY FootballPlayers.Last_Name;

但是我不知道如果成功转移的次数超过3，如何添加条件

Answer 1

由于这是一个组场景，在GROUP BY你可能想要：

HAVING COUNT(1) > 3

HAVING子句的工作方式与WHERE非常相似，但应用方式不同。

---

另一种方法是子查询：

SELECT * FROM
(
    SELECT FootballPLayers.Last_Name,
        SUM(CASE acceptance WHEN 'yes' THEN price ELSE 0 END) AS amount_price,
        COUNT(1) AS [Transfers]
    FROM  FootballPlayers 
    INNER JOIN Transfers ON FootballPlayers.ID_footballplayer = Transfers.code_footballplayer
    GROUP BY FootballPlayers.Last_Name
) x
WHERE x.Transfers > 3