sql - Check whether string is a date Postgresql

Question

Is there any function in PostgreSQL that returns Boolean whether a given string is a date or not just like ISDATE() in MSSQL?

ISDATE("January 1, 2014")

Answer 1

You can create a function:

create or replace function is_date(s varchar) returns boolean as $$
begin
  perform s::date;
  return true;
exception when others then
  return false;
end;
$$ language plpgsql;

Then, you can use it like this:

postgres=# select is_date('January 1, 2014');
 is_date
---------
 t
(1 row)

postgres=# select is_date('20140101');
 is_date
---------
 t
(1 row)

postgres=# select is_date('20140199');
 is_date
---------
 f
(1 row)