postgres=# CREATE FUNCTION "double_price" (double precision) RETURNS double precision AS '
postgres'# DECLARE
postgres'# BEGIN
postgres'# return $1 * 2;
postgres'# END;
postgres'# ' LANGUAGE 'plpgsql';
CREATE FUNCTION
postgres=#
postgres=# select double_price(10);
double_price
--------------
20
(1 row)
postgres=#