SELECT SUM((url1 IS NOT NULL AND url1 <> '') +
(url2 IS NOT NULL AND url2 <> '') +
(url3 IS NOT NULL AND url3 <> '') +
(url4 IS NOT NULL AND url4 <> '') +
(url5 IS NOT NULL AND url5 <> '') +
(url6 IS NOT NULL AND url6 <> '') +
(url7 IS NOT NULL AND url7 <> '') +
(url8 IS NOT NULL AND url8 <> '')
) AS TOTAL FROM lentele WHERE id = '$id';