mysql> select * from test;

+----+------------+-------+-----------+

| id | name       | score | subject   |

+----+------------+-------+-----------+

|   | xiaoming   |     | shuxue    |

|   | xiaohong   |     | shuxue    |

|   | xiaohong   |     | english   |

|   | xiaohong   |     | physics   |

|   | xiaohong   |     | astronaut |

|   | xiaoming   |     | physics   |

|   | xiaoming   |     | astronaut |

|   | xiaoming   |     | english   |

|   | xiaobai    |     | astronaut |

|  | .2xiaobai |     | english   |

|  | .2xiaobai |     | physics   |

|  | 3xiaobai   |     | shuxue    |

|  | 123xiaohei |     | astronaut |

|  | xiaohei    |     | shuxue    |

|  | xiaohei    |     | physics   |

|  | .12xiaohei |     | english   |

+----+------------+-------+-----------+

 rows in set (0.00 sec)

mysql> select locate("xiao",name) from test where id=;

+---------------------+

| locate("xiao",name) |

+---------------------+

|                    |

+---------------------+

 row in set (0.00 sec)

mysql> select locate("iao",name) from test where id=;

+--------------------+

| locate("iao",name) |

+--------------------+

|                   |

+--------------------+

 row in set (0.00 sec)

mysql> select locate("o",name) from test where id=;

+------------------+

| locate("o",name) |

+------------------+

|                 |

+------------------+

 row in set (0.00 sec)

mysql> select locate("o",name,) from test where id=;

+--------------------+

| locate("o",name,) |

+--------------------+

|                   |

+--------------------+

 row in set (0.00 sec)