DELIMITER //
DROP PROCEDURE PROC_SEARCH_LIBRARY//
CREATE PROCEDURE PROC_SEARCH_LIBRARY (PARAM_SEARCH_ARTIST VARCHAR(256), PARAM_SEARCH_ALBUM VARCHAR(256), PARAM_SEARCH_TRACK VARCHAR(256), PARAM_NUM_RESULT VARCHAR(4))
BEGIN
 	SET @SQL_QUERY = CONCAT("	SELECT  GENRES.ID_GENRE, 
						ALBUMS.ID_ALBUM, 
						TRACKS.ID_TRACK, 
						TRACKS.META_ARTIST, 
						TRACKS.META_ALBUM, 
						TRACKS.META_TRACK, 
						CONCAT(OPT.PATH_BASE, "/", PATH_GENRE, "/", PATH_ALBUM, "/", PATH_TRACK) AS PATH_TRACK 
					FROM 	TRACKS, ALBUMS, GENRES, 
						(SELECT FUNC_GET_OPTION('BasePath') AS PATH_BASE) OPT 
					WHERE 	TRACKS.ID_ALBUM = ALBUMS.ID_ALBUM 
					AND 	ALBUMS.ID_GENRE = GENRES.ID_GENRE 
					AND 	TRACKS.META_ARTIST LIKE '%", PARAM_SEARCH_ARTIST, "%' 
					AND 	TRACKS.META_ALBUM LIKE '%", PARAM_SEARCH_ALBUM, "%' 
					AND 	TRACKS.META_TRACK LIKE '%", PARAM_SEARCH_TRACK, "%' 
					LIMIT ", PARAM_NUM_RESULT);
	PREPARE PREP_SQL_QUERY FROM @SQL_QUERY;
	EXECUTE PREP_SQL_QUERY;
	DEALLOCATE PREPARE PREP_SQL_QUERY;
END;//


CALL PROC_SEARCH_LIBRARY('hireo','3rd','','10');

Error Code : 1064
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'NULL' at line 1
(0 ms taken)