Question

我要做的是从数据库中查询所有唯一的地区名称，并在每个地区名称上获取相应的MIN和MAX ID。

这就是我现在所拥有的：

SELECT DISTINCT DISTRICTNAME, 
(SELECT MIN(`ID`)
    FROM [DATABASE_NAME]
        WHERE DISTRICTNAME = DISTRICTNAME) AS 'MIN', 
(SELECT MAX(`ID`) 
    FROM [DATABASE_NAME]
        WHERE DISTRICTNAME = DISTRICTNAME) AS 'MAX'
FROM [DATABASE_NAME]
WHERE [CONDITION]
ORDER BY DISTRICTNAME;

问题：MIN和MAX列显示相同的值。我不太确定我的内部查询的WHERE子句。我认为这就是问题所在。

帮助？

Answer 1

使用GROUP BY子句

尝试此查询

SELECT DISTRICTNAME, MIN(`ID`) AS 'MIN', MAX(`ID`) AS 'MAX'
FROM [DATABASE_NAME]
WHERE [CONDITION]
GROUP BY DISTRICTNAME
ORDER BY DISTRICTNAME;;

在内部查询中使用外部查询中的结果

1 个答案: