mysql字符串函数之length,char_length用法

语法

LENGTH(str)

Returns the length of the string str, measured in bytes. A multibyte character counts as multiple bytes. This means that for a string containing five 2-byte characters, LENGTH() returns 10, whereas CHAR_LENGTH() returns 5.

返回字符串str的长度，以字节为单位。 多字节字符计为多个字节。 这意味着对于包含5个2字节字符的字符串，LENGTH（）返回10，而CHAR_LENGTH（）返回5。

CHAR_LENGTH(str)

Returns the length of the string str, measured in characters. A multibyte character counts as a single character. This means that for a string containing five 2-byte characters, LENGTH() returns 10, whereas CHAR_LENGTH() returns 5.

返回字符串str的长度，以字符为单位。 多字节字符算作单个字符。 这意味着对于包含5个2字节字符的字符串，LENGTH（）返回10，而CHAR_LENGTH（）返回5。

实例

SELECT length('aaa');           # 3
SELECT length('ɠɠɠ');           # 6
SELECT length('我我我');         # 9

SELECT char_length('aaa');      # 3
SELECT char_length('ɠɠɠ');      # 3
SELECT char_length('我我我');    # 3