如何计算 MySQL 中每一列的数据？答案

【问题标题】：how to counting data from each column in MySQL?如何计算 MySQL 中每一列的数据？
【发布时间】：2010-09-17 04:25:36
【问题描述】：

我有一些用于数据透视表的 mysql 脚本，然后计算其中的一些数据：

SELECT A.Line,
       week1.1stweek, week2.2ndweek,
       IFNULL(week1.1stweek,0) + IFNULL(week2.2ndweek,0) AS TOTAL
FROM inspection_report AS A
LEFT JOIN(
           SELECT Line, (SUM(S) + SUM(A) + SUM(B)*0.4 + SUM(C)*0.1)/COUNT(Serial_number) AS 1stweek
           FROM inspection_report
           WHERE DAY(Inspection_datetime) BETWEEN 1 AND 7
           GROUP BY Line, WEEK(Inspection_datetime), YEAR(Inspection_datetime)
          ) AS week1 USING (Line)
LEFT JOIN(
           SELECT Line, (SUM(S) + SUM(A) + SUM(B)*0.4 + SUM(C)*0.1)/COUNT(Serial_number) AS 2ndweek
           FROM inspection_report
           WHERE DAY(Inspection_datetime) BETWEEN 8 AND 14
           GROUP BY Line, WEEK(Inspection_datetime), YEAR(Inspection_datetime)
          ) AS week2 USING (Line)
GROUP BY Line

它使表头显示为按钮。之后我想在每一列下面做一个“SUM”：

Line          1stweek            2ndweek             total
1               12                 2                   14
2               3                  0                    3
SUM             15                 2                   17

我该怎么做？

【问题讨论】：

标签： mysql count pivot-table

【解决方案1】：

使用WITH ROLLUP 修饰符。

http://dev.mysql.com/doc/refman/5.0/en/group-by-modifiers.html

你必须修改外部选择语句

SELECT A.Line,
       sum(week1.1stweek) as 1stweek, sum(week2.2ndweek) 2ndweek,
       sum(IFNULL(week1.1stweek,0) + IFNULL(week2.2ndweek,0)) AS TOTAL

使修饰符生效。如果您需要这样标记，请将 A.Line 更改为 IFNULL(A.Line, "SUM") as Line。

【讨论】：

但它没有计算全部。它只显示每列的最后一个数据。
在使用 IFNULL(A.Line, "SUM") 作为 Line 之后，“SUM”没有显示在下面仍然是“null”。为什么会发生？
你能把你的sql语句现在是什么样子的吗？
我发布了我的数据库结构，所以你可以试试。
我已经找到了答案。在我使用 GROUP BY Line WITH ROLL UP 之前。在我使用 IFNULL(A.Line, "SUM") 作为 Line 并且不要忘记使用 GROUP BY A.Line WITH ROLLUP 之后。

【解决方案2】：

这让我很感兴趣，所以我在一个在线 SQL 沙箱中实现了一个等价物，here。

select ifnull(toy, "SUM") as toy, sum(s1.store1) as store2, sum(s2.store2) as store1, sum(ifnull(store1,0)+ifnull(store2,0)) as total from (select toy_id, sum(inventory) as store1 from store_inventory where store_id=1 group by toy_id) as s1 left join (select toy_id, sum(inventory) as store2 from store_inventory where store_id=2 group by toy_id) as s2 using (toy_id) left join toy_info using (toy_id) group by toy with rollup;

（请原谅我缺乏降价技巧，这是我的第一篇文章。）

【讨论】：