How to multiply numbers in a column in MySQL(lists.mysql.com)

    CREATE OR REPLACE FUNCTION product_sfunc(state NUMERIC, value NUMERIC) 
    RETURNS NUMERIC AS $$ 
    BEGIN
        IF value IS NOT NULL THEN
            IF state IS NULL THEN 
                RETURN value;
            ELSE
                RETURN state * value;
            END IF;
        END IF;
        RETURN state;
    END; $$ LANGUAGE plpgsql;
    
    CREATE AGGREGATE PRODUCT (NUMERIC) (
        SFUNC = product_sfunc,
        STYPE = NUMERIC
    );

    SELECT SUM(n), PRODUCT(n) from generate_series(1, 5) as n;
     sum | product
    -----+---------
      15 |     120

    SELECT n, PRODUCT(n) OVER (ORDER BY n) from generate_series(1, 5) as n;
     n | product
    ---+---------
     1 |       1
     2 |       2
     3 |       6
     4 |      24
     5 |     120