How to declare a variable in a PostgreSQL query

Question

How do I declare a variable for use in a PostgreSQL 8.3 query?

In MS SQL Server I can do this:

DECLARE @myvar INT
SET @myvar = 5

SELECT *
FROM somew         


        

Answer 1

Using a Temp Table outside of pl/PgSQL

Outside of using pl/pgsql or other pl/* language as suggested, this is the only other possibility I could think of.

begin;
select 5::int as var into temp table myvar;
select *
  from somewhere s, myvar v
 where s.something = v.var;
commit;