drop function if exists diakNaploSorszam;

 DELIMITER //
 CREATE function diakNaploSorszam ( thisDiakId INT, thisTanev INT, thisOsztalyId INT ) returns INT
 READS SQL DATA
 BEGIN
    DECLARE inKezdesDt,inZarasDt DATE;
    DECLARE a,i INT; -- for loop
    DECLARE b DATE; -- for loop
    DECLARE cur1
        CURSOR FOR
        SELECT diakId,IF(beDt<inKezdesDt,inKezdesDt,beDt) AS d FROM osztalyDiak LEFT JOIN diak USING (diakId) WHERE osztalyId=thisOsztalyId AND beDt<=inZarasDt AND (kiDt IS NULL OR kiDt>=inKezdesDt) ORDER BY d, CONCAT_WS(' ',viseltCsaladinev,viseltUtonev) COLLATE utf8_hungarian_ci;
    DECLARE CONTINUE HANDLER FOR NOT FOUND RETURN NULL;

    SELECT kezdesDt FROM szemeszter WHERE tanev=thisTanev AND szemeszter=1 INTO inKezdesDt;
    SELECT MAX(zarasDt) FROM szemeszter WHERE tanev=thisTanev INTO inZarasDt;
    SET i := 1;
    OPEN cur1;
    lo: LOOP
        FETCH cur1 INTO a,b;
        IF a = thisDiakId THEN
            LEAVE lo;
        END IF;
        SET i := i+1;
    END LOOP;
    CLOSE cur1;
    return i;
 END; //
 DELIMITER ; //