mysql字符串函数详细汇总

MySQL字符串函数是用于处理和操作字符串数据的一系列内置函数，这些函数可以帮助我们轻松地完成各种字符串操作，如截取、替换、拼接等，本文将对MySQL中的常用字符串函数进行详细的汇总介绍。

字符串长度函数

1、CHAR_LENGTH()：返回字符串的字符数。

语法：CHAR_LENGTH(str)

2、CHARACTER_LENGTH()：返回字符串的字符数。

语法：CHARACTER_LENGTH(str)

3、LENGTH()：返回字符串的字节数。

语法：LENGTH(str)

4、LENGTHB()：返回字符串的字节数。

语法：LENGTHB(str)

字符串截取函数

1、SUBSTRING()：从字符串中截取子串。

语法：SUBSTRING(str, pos, len)

2、MID()：从字符串中截取子串。

语法：MID(str, pos, len)

3、LEFT()：从字符串左侧截取指定长度的子串。

语法：LEFT(str, len)

4、RIGHT()：从字符串右侧截取指定长度的子串。

语法：RIGHT(str, len)

5、SUBSTR()：从字符串中截取子串。

语法：SUBSTR(str, pos, len)

字符串替换函数

1、REPLACE()：替换字符串中的子串。

语法：REPLACE(str, from_str, to_str)

2、REPLACE()：替换字符串中的子串。

语法：REPLACE(str, from_str, to_str)

字符串拼接函数

1、CONCAT()：连接两个或多个字符串。

语法：CONCAT(str1, str2, ..., strN)

2、CONCAT_WS()：连接两个或多个字符串，可以指定分隔符。

语法：CONCAT_WS(separator, str1, str2, ..., strN)

字符串查找函数

1、LOCATE()：查找子串在字符串中的位置。

语法：LOCATE(substr, str, [start])

2、INSTR()：查找子串在字符串中的位置。

语法：INSTR(str, substr)

3、POSITION()：查找子串在字符串中的位置。

语法：POSITION(substr IN str)

字符串匹配函数

1、LIKE()：判断一个字符串是否匹配给定的模式。

语法：LIKE pattern ESCAPE 'escape_char'

2、REGEXP()：使用正则表达式匹配字符串。

语法：REGEXP pattern MODE modifiers 'i' 'c' 'n' 'm' 'x' 'o' 'u' 's' 'e' 'g' 'p' 'w' '+' '*' '?' '(' ')' '[' ']' '{' '}' '|' '\' '\'' '\'' '\'' ''' '\'' '\'' '\'' ''' '\'' '\'' '\'' ''' '\'' '\'' '\'' ''' '\'' '\'' '\'' ''' '\'' '\'' '\'' ''' '\'' '\'' '\'' ''' '\'' '\'' '\'' ''' '\'' '\'' '\'' ''' '\'' '\'' '\'' ''' '\'' '\'' '\'' ''' '\'' '\'' '\'' ''' '\'' '\'' '\--' '+' '*' '?' '(' ')' '[' ']' '{' '}' '|' '\\' '\--' '+' '*' '?' '(' ')' '[' ']' '{' '}' '|' '\\' '--' '+' '*' '?' '(' ')' '[' ']' '{' '}' '|' '\\' '\--' '+' '*' '?' '(' ')' '[' ']' '{' '}' '|' '\' '\--' '+' '*' '?' '(' ')' '[' ']' '{' '}' '|' '\\' '\--' '+' '*' '?' '(' ')' '[' ']' '{' '}' '|' '\\' '\--' '+' '*' '?' '(' ')' '[' ']' '{' '}' '|' 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INSTR()函数和LOCATE()函数有什么区别？