postgres=# -- Variable Declarations
postgres=#
postgres=# CREATE FUNCTION identifier () RETURNS int4 AS '
postgres'# DECLARE
postgres'#
postgres'# -- Declare an integer.
postgres'# subject_id INTEGER;
postgres'#
postgres'# -- Declare a variable length character.
postgres'# book_title VARCHAR(10);
postgres'#
postgres'# -- Declare a floating point number.
postgres'# book_price FLOAT;
postgres'#
postgres'# BEGIN
postgres'# return 10;
postgres'# END;
postgres'# ' LANGUAGE 'plpgsql';
ERROR: function "identifier" already exists with same argument types
postgres=#
postgres=# select identifier();
identifier
------------
10
(1 row)
postgres=#
postgres=# drop function identifier();
DROP FUNCTION
postgres=#
postgres=#