mysql> select t1.tid,t1.uid,t2.userid,t2.username from talk_rec t1 left join (select userid,username from t_users) t2 on t1.uid=t2.userid limit 10;
+-----+------------------+------------------+----------+
| tid | uid | userid | username |
+-----+------------------+------------------+----------+
| 617 | 1504201737464577 | 1504201737464577 | 奋斗ing |
| 618 | 1504301648534989 | 1504301648534989 | CER |
| 620 | 1504301648534989 | 1504301648534989 | CER |
| 621 | 1504301648534989 | 1504301648534989 | CER |
| 622 | 1504301648534989 | 1504301648534989 | CER |
| 623 | 1504201737464577 | 1504201737464577 | 奋斗ing |
| 627 | 1504201737464577 | 1504201737464577 | 奋斗ing |
| 628 | 1504201737464577 | 1504201737464577 | 奋斗ing |
| 629 | 1504201737464577 | 1504201737464577 | 奋斗ing |
| 630 | 1504301648534989 | 1504301648534989 | CER |
+-----+------------------+------------------+----------+
10 rows in set
sql语句可以join一个子查询结果进行查询, 注意关联的时候，需要关联的字段一定要在子查询中被查询出来。