SELECT n.nspname AS schema_name
, p.proname AS function_name
, pg_get_function_arguments(p.oid) AS args
, pg_get_functiondef(p.oid) AS func_def
FROM pg_proc p
JOIN pg_namespace n ON n.oid = p.pronamespace
AND n.nspname = 'schema_name'
AND p.prosrc like '%table_name%'