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