source: database/Advanced Reports for database/Approximate number of orders per client@ 62b2964

CREATE OR REPLACE FUNCTION get_approximate_orders_per_client()
RETURNS TABLE (
    total_clients BIGINT,
    total_orders BIGINT,
    approximate_orders_per_client NUMERIC
)
LANGUAGE plpgsql
AS $$
BEGIN
    RETURN QUERY
    SELECT
        (SELECT COUNT(*) FROM client) AS total_clients,
        (SELECT COUNT(*) FROM "order") AS total_orders,
        ROUND(
            (SELECT COUNT(*) FROM "order")::NUMERIC
            / NULLIF((SELECT COUNT(*) FROM client), 0),
            2
        ) AS approximate_orders_per_client;
END;
$$;