postgresql - Postgres query to check a string is a number

Question

Can anyone tell me the query to check whether a string is a number(double precision). It should return true if the string is number. else it should return false.

consider :

       s1 character varying;
       s2 character varying;

       s1 ='12.41212' => should return true
       s2 = 'Service' => should return false

Answer 1

I think the easiest way would be a regular expression match:

select '12.41212' ~ '^[0-9.]+$'
=> true

select 'Service' ~ '^[0-9.]+$'
=> false