trim()函数 mysql中的强大字符串过滤函数

mysql中功能强大的trim()函数.

去除两边空格：

mysql> select trim(' hello world ');

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

| trim(' hello world ') |

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

| hello world           |

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

1 row in set

去除左边空格：

select ltrim(' hello world ');

去除右边空格：

select rtrim(' hello world ');

trim函数还可以过滤指定字符串：

去除两边逗号：

mysql> SELECT TRIM(BOTH ',' FROM ',a,b,c,');

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

| TRIM(BOTH ',' FROM ',a,b,c,') |

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

| a,b,c                         |

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

1 row in set

去除左边逗号：

mysql> SELECT TRIM(LEADING ',' FROM ',,,abc');

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

| TRIM(LEADING ',' FROM ',,,abc') |

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

| abc                             |

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

1 row in set

去除右边逗号：

mysql> SELECT TRIM(TRAILING ',' FROM ',,,abc,,,,,');

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

| TRIM(TRAILING ',' FROM ',,,abc,,,,,') |

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

| ,,,abc                                |

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

1 row in set