CREATE DEFINER=`root`@`%` FUNCTION `Validar_Nit`(tcNit varchar(15)) RETURNS int(11)
BEGIN
    DECLARE lcDato, lcChar VARCHAR(15) DEFAULT '';
    DECLARE lnItem, lnSuma, lnRetorno INT DEFAULT 0;
    SET lcDato := RIGHT(CONCAT(SPACE(15), TRIM(tcNit)), 15);
    REPEAT
       SET lnItem := lnItem + 1;
       SET lcChar := SUBSTR(lcDato FROM lnItem FOR 1);
       SET lnSuma := lnSuma + (lcChar * ELT(lnItem, 71, 67, 59, 53, 47, 43, 41, 37, 29, 23, 19, 17, 13, 7, 3));
    UNTIL lnItem = 15
    END REPEAT;
    SET lnSuma := MOD(lnSuma, 11);
    IF lnSuma = 0 OR lnSuma = 1 THEN
       SET lnRetorno := lnSuma;
    ELSE
       SET lnRetorno := 11 - lnSuma;
    END IF;
    RETURN lnRetorno;
END