sql - 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 somewhere
WHERE something = @myvar

How do I do the same in PostgreSQL? According to the documentation variables are declared simply as "name type;", but this gives me a syntax error:

myvar INTEGER;

Could someone give me an example of the correct syntax?

Answer 1

I accomplished the same goal by using a WITH clause, it's nowhere near as elegant but can do the same thing. Though for this example it's really overkill. I also don't particularly recommend this.

WITH myconstants (var1, var2) as (
   values (5, 'foo')
)
SELECT *
FROM somewhere, myconstants
WHERE something = var1
   OR something_else = var2;