mysql> select * from test;+----+------------+-------+-----------+| id | name       | score | subject   |+----+------------+-------+-----------+|  1 | xiaoming   |    89 | shuxue    ||  2 | xiaohong   |    89 | shuxue    ||  3 | xiaohong   |    80 | english   ||  4 | xiaohong   |    80 | physics   ||  5 | xiaohong   |    80 | astronaut ||  6 | xiaoming   |    80 | physics   ||  7 | xiaoming   |    80 | astronaut ||  8 | xiaoming   |    80 | english   ||  9 | xiaobai    |    80 | astronaut || 10 | 1.2xiaobai |    80 | english   || 11 | 2.2xiaobai |    80 | physics   || 12 | 3xiaobai   |    80 | shuxue    || 13 | 123xiaohei |    80 | astronaut || 14 | xiaohei    |    80 | shuxue    || 15 | xiaohei    |    80 | physics   || 16 | .12xiaohei |    80 | english   |+----+------------+-------+-----------+16 rows in set (0.00 sec)mysql> select * from test where name in (select name from test where score=89);+----+----------+-------+-----------+| id | name     | score | subject   |+----+----------+-------+-----------+|  1 | xiaoming |    89 | shuxue    ||  2 | xiaohong |    89 | shuxue    ||  3 | xiaohong |    80 | english   ||  4 | xiaohong |    80 | physics   ||  5 | xiaohong |    80 | astronaut ||  6 | xiaoming |    80 | physics   ||  7 | xiaoming |    80 | astronaut ||  8 | xiaoming |    80 | english   |+----+----------+-------+-----------+8 rows in set (0.01 sec)