How to fetch specific data using regular expression in postgres sql

Question

I need to fetch the values of a column if it contains special characters other than alphanumeric.

Ex: select name from data;

name

ACD12
A12DD
A_C12
A@CD
AB_M1
123AB

I need to write a regular expression to fetch the following data from the above table:

A_C12
A@CD
AB_M1

Answer 1

You need an expression that says "Any string that contains at least one non-alpha-numeric character":

SELECT name FROM table1 WHERE name ~ '[^[:alnum:]]'

See: http://sqlfiddle.com/#!12/2edd5/15

I haven't used \W because it's equivalent to [^[:alnum:]_] and you don't want the underscore. See the PostgreSQL docs on regular expressions.