正则表达式

regexp_replace('string','[a-zA-Z0-9[:punct:]\uff00-\uffef。『』]','','g')

[[:alpha:]] 代表 字母
[[:alnum:]] 代表 字母与数字字符

给你一个英文版的解释：
[:alnum:]'
     Alphanumeric characters: `[:alpha:]' and `[:digit:]'.

`[:alpha:]'
     Alphabetic characters: `[:lower:]' and `[:upper:]'.

`[:blank:]'
     Blank characters: space and tab.

`[:cntrl:]'
     Control characters.  In ASCII, these characters have octal codes
000 through 037, and 177 (`DEL'). In other character sets, these
     are the equivalent characters, if any.

`[:digit:]'
     Digits: `0 1 2 3 4 5 6 7 8 9'.

`[:graph:]'
     Graphical characters: `[:alnum:]' and `[:punct:]'.

`[:lower:]'
Lower-case letters: `a b c d e f g h i j k l m n o p q r s t u v w
     x y z'.
`[:print:]'
     Printable characters: `[:alnum:]', `[:punct:]', and space.

`[:punct:]'
     Punctuation characters: `! " # $ % & ' ( ) * + , - . / : ; < = > ?
     @ [ \ ] ^ _ `  ~'.

`[:space:]'
     Space characters: tab, newline, vertical tab, form feed, carriage
     return, and space.

`[:upper:]'
     Upper-case letters: `A B C D E F G H I J K L M N O P Q R S T U V W
     X Y Z'.

`[:xdigit:]'
     Hexadecimal digits: `0 1 2 3 4 5 6 7 8 9 A B C D E F a b c d e f'.