Question

我有table1这样：

ID uid jid type val
1   1   1   1   1
2   1   1   1   10
3   1   2   1   100
4   1   3   1   1000
5   1   4   2   2

加入table2：

ID uid jid stat time
1   1   1   1   100
2   1   1   1   200
3   1   1   4   300
4   1   2   2   400

我尝试从table1获取val的SUM，通过uid对其进行分组，并通过此查询键入并连接table2：

SELECT a.uid, a.type, SUM(a.val) as t1, SUM(a.val)*COUNT(distinct(a.id))/COUNT(a.id) as t2, MAX(b.time) as max_time
FROM table1 as a
LEFT JOIN table2 as b on b.uid = a.uid and b.jid = a.jid and b.stat = 1
GROUP BY a.uid, a.type

结果我得到了这个值：

uid type t1     t2     max_time
1   1   1122  748.0000  200
1   2      2    2.0000  NULL

但类型= 1的总数应为：1111（不是1122而不是748）

请告诉我我做错了什么。

Answer 1

您需要在select语句中使用带有a.uid的DISTINCT。更正的查询如下：

SELECT DISTINCT（a.uid），a.type，SUM（a.val）AS t1，SUM（a.val）* COUNT（DISTINCT（a.id））/ COUNT（a.id）AS t2， MAX（b.time）AS max_time FROM table1 AS a LEFT JOIN table2 AS b ON b.uid = a.uid AND b.jid = a.jid AND b.stat = 1 GROUP BY a.uid，a.type

Answer 2

你可以重新检查sql：

SELECT auid，atype，SUM（aval），SUM（aval）* COUNT（DISTINCT（援助））/ COUNT（援助）AS t2，MAX（btime）AS max_time 从（ SELECT DISTINCT（a.uid）AS auid，a.type AS atype，a.val AS aval，a.id AS aid，b.time AS btime FROM table1 AS a LEFT JOIN table2 AS b ON b.uid = a.uid AND b.jid = a.jid AND b.stat = 1 ）AS grouptable GROUP BY auid，atype

我得到的输出：

auid atype sum（aval）t2 max_time

1 1 1111 1111.0000 200

1 2 2 2.0000（NULL）

您正在寻找的结果是什么？

用连接表分组并计算总和

2 个答案: