Stored procedure call with PostgreSQL

PostgreSQL implements stored functions that can return values. If the function returns more that one value, you must specify the returning values as function parameters with the OUT keyword. If the function returns a unique value, you can use the RETURNS clause.

Pay attention to the function signature; PostgreSQL allows function overloading. For example, func(int) and func(char) are two different functions. To drop a function, you must specify the parameter type to identify the function signature properly.