@alsotang 你没跑过你的SQL吧，会报错的，亲。给你修改一下改成
select a1.aid from a as a1 inner join a as a2 where a1.bid = 47 and a1.bid = 22 and a1.aid = a2.aid;
这下不报错了，结果返回 Empty set (0.00 sec)
用我的sql实验，返回的是

+------+
| aid |
+------+
| 100 |
+------+
1 row in set (0.00 sec)

我建的测试数据库数据和LZ给出的一致。

explain分析一下你的语句就知道错误在那里了


mysql> EXPLAIN
-> select a1.aid from table_a as a1 inner join table_a as a2 where a1.bid = 47 and a1.bid = 22 and a1.aid = a2.aid;
+----+-------------+-------+------+---------------+------+---------+------+------+------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-------+------+---------------+------+---------+------+------+------------------+
| 1 | SIMPLE | NULL | NULL | NULL | NULL | NULL | NULL | NULL | Impossible WHERE |
+----+-------------+-------+------+---------------+------+---------+------+------+------------------+


Impossible WHERE