How to fix PGRST118: Could not find function in Supabase

-- Execute this in the Supabase SQL Editor
NOTIFY pgrst, 'reload config';

-- Force PostgREST backend to reload
SELECT pg_terminate_backend(pid)
FROM pg_stat_activity
WHERE application_name = 'postgrest';

-- List all functions in the public schema
SELECT n.nspname as schema_name,
       p.proname as function_name,
       pg_get_functiondef(p.oid) as function_definition
FROM pg_proc p
JOIN pg_namespace n ON p.pronamespace = n.oid
WHERE n.nspname = 'public'
AND p.proname = 'my_function';

CREATE OR REPLACE FUNCTION my_function(p_user_id INT)
RETURNS TABLE (user_name TEXT, email TEXT) AS $$
BEGIN
  RETURN QUERY
  SELECT name, email FROM users WHERE id = p_user_id;
END;
$$ LANGUAGE plpgsql;

-- For authenticated users
GRANT EXECUTE ON FUNCTION my_function(p_user_id INT) TO authenticated;

-- For public/anonymous users
GRANT EXECUTE ON FUNCTION my_function(p_user_id INT) TO anon;

-- For service role (admin operations)
GRANT EXECUTE ON FUNCTION my_function(p_user_id INT) TO service_role;

-- For all roles
GRANT EXECUTE ON FUNCTION my_function(p_user_id INT) TO PUBLIC;

-- Check function permissions
SELECT grantee, privilege_type
FROM information_schema.role_routine_grants
WHERE routine_schema = 'public'
AND routine_name = 'my_function';

-- Function defined with lowercase
CREATE OR REPLACE FUNCTION get_user(p_user_id INT)
RETURNS TABLE (id INT, name TEXT) AS $$
...

// JavaScript - WRONG: using camelCase when function expects snake_case
const { data, error } = await supabase.rpc('get_user', { pUserId: 123 });
// Error: PGRST118 - could not find function

// JavaScript - CORRECT: matching parameter names exactly
const { data, error } = await supabase.rpc('get_user', { p_user_id: 123 });

-- Find what schema your function is in
SELECT n.nspname as schema_name, p.proname as function_name
FROM pg_proc p
JOIN pg_namespace n ON p.pronamespace = n.oid
WHERE p.proname = 'my_function';

CREATE OR REPLACE FUNCTION public.my_function(p_user_id INT)
RETURNS TABLE (id INT, name TEXT) AS $$
...

-- Function definition with specific parameters
CREATE OR REPLACE FUNCTION add_numbers(a INT, b INT)
RETURNS INT AS $$
SELECT a + b;
$$ LANGUAGE sql;

// WRONG: Missing required parameter
const { data, error } = await supabase.rpc('add_numbers', { a: 5 });
// Error: PGRST118

// CORRECT: All required parameters provided
const { data, error } = await supabase.rpc('add_numbers', { a: 5, b: 3 });

// CORRECT: Parameterless function
const { data, error } = await supabase.rpc('get_current_timestamp', {});

-- View function details including parameter count
SELECT p.proname,
       p.pronargs as parameter_count,
       pg_get_functiondef(p.oid) as definition
FROM pg_proc p
WHERE p.proname = 'my_function';