create_function_call_function_retrieve_function_definitions_postgresql.sql

# Create function
CREATE OR REPLACE FUNCTION get_organization_id_by_user_id(p_user_id INTEGER)
RETURNS INTEGER AS $$
DECLARE
  v_organization_id INTEGER;
BEGIN
  SELECT organization
  INTO v_organization_id
  FROM users
  WHERE id = p_user_id;

  RETURN v_organization_id;
END;
$$ LANGUAGE plpgsql;

# Call it
select get_organization_id_by_user_id(1)


# View all functions
SELECT
  n.nspname AS schema_name,
  p.proname AS function_name,
  pg_get_function_arguments(p.oid) AS function_arguments
FROM
  pg_proc p
JOIN pg_namespace n ON p.pronamespace = n.oid
WHERE
  n.nspname NOT LIKE 'pg_%' AND
  n.nspname != 'information_schema'
ORDER BY
  schema_name,
  function_name;


# View function definition by name
SELECT prosrc FROM pg_proc WHERE proname = 'function_name';