小编Mat*_*nco的帖子

看看这两个查询：

简单的：

mysql> SELECT * FROM omgbatch JOIN omgoutput ON (idomgbatch=omgbatch) WHERE idomgoutput = (SELECT DISTINCT lastoutput FROM omgenvelope WHERE lastinput=18658);
+------------+-------+------------+------- ------+---------+----------+
| idomgbatch | 芦丁 | 批处理时间 | idmgoutput | 流量模式 | omgbatch |
+------------+-------+------------+------- ------+---------+----------+
| 12174 | 8 | 20140508040930-832 | 10728 | 162 | 12174 |
+------------+-------+------------+------- ------+---------+----------+
1 行（0.00 秒）

和

复杂的：

mysql> SELECT * FROM omgbatch JOIN omgoutput ON (idomgbatch=omgbatch) WHERE idomgoutput IN (SELECT DISTINCT lastoutput FROM omgenvelope WHERE lastinput=18658);
+------------+-------+------------+------- ------+---------+----------+
| …