我有下面 2 个表格:
Table1
+-----------+------------+-----------+-----------+
| date | TRAFFIC1 | PAYLOAD11 | PAYLOAD12 |
+-----------+------------+-----------+-----------+
|2015-01-01 | 2 | 2 | 2 |
|2015-01-01 | 3 | 3 | 3 |
|2015-01-02 | 2 | 2 | 2 |
|2015-01-02 | 3 | 3 | 3 |
+-----------+------------+-----------+-----------+
Table2
+-----------+------------+-----------+-----------+
| date | TRAFFIC21 | PAYLOAD21 | PAYLOAD22 |
+-----------+------------+-----------+-----------+
|2015-01-01 | 2 | 2 | 2 |
|2015-01-01 | 3 | 3 | 3 |
|2015-01-02 | 2 | 2 | 2 |
|2015-01-02 | 3 | 3 | 3 |
+-----------+------------+-----------+-----------+
我想按日期对上面 2 个表中的有效负载求和？
最佳答案
SELECT date, SUM(payload) FROM (
SELECT date, `PAYLOAD11` + `PAYLOAD12` as payload FROM Table1
union all
SELECT date, `PAYLOAD21` + `PAYLOAD22` as payload FROM Table2) grp
GROUP BY date
<强> SQLFIDDLE
关于mysql - 对表的列求和，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/27917773/