$SelSil = 'SELECT SUM(album_duration) as totalAlbumDuration FROM `shk_album` WHERE idshk2 = "'.$id_shk.'" GROUP BY idshk2';

c'est une recherche sur un nom du chanteur, que je veux afficher la duree de chaque album ainsi que la duree totale des albums:

Duree totale des albums est: XXXXXX
Taille totale des albums est yyyyy

CREATE TABLE IF NOT EXISTS `shk_tbl` (
  `id_shk` int(5) NOT NULL AUTO_INCREMENT,
  `shk_fname` varchar(30) COLLATE utf8_unicode_ci NOT NULL COMMENT 'first name',
  `shk_mname` varchar(200) COLLATE utf8_unicode_ci NOT NULL COMMENT 'middle name',
  `shk_lname` varchar(30) COLLATE utf8_unicode_ci NOT NULL COMMENT 'last name',
  PRIMARY KEY (`id_shk`)
) ENGINE=MyISAM  DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

CREATE TABLE IF NOT EXISTS `shk_album` (
  `id_alb` int(5) NOT NULL AUTO_INCREMENT,
  `idshk2` int(3) NOT NULL,
  `album_name` varchar(10) COLLATE utf8_unicode_ci NOT NULL DEFAULT '0',
  `album_duration` decimal(20,10) NOT NULL DEFAULT '0.0000000000',
  `album_size` varchar(10) COLLATE utf8_unicode_ci NOT NULL DEFAULT '0',
  PRIMARY KEY (`id_mus`)
) ENGINE=MyISAM  DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

<?php

// je selectionne les chanteurs
	$Selsh = 'SELECT id_shk FROM shk_tbl WHERE shk_fname LIKE "%'.$shkName.'%"';
	//echo $Selsh.'<br />';
	$Reqsh = $connexion->query($Selsh);
	$Ressh = $Reqsh->fetchAll();
	
// j'obtien l'id de chaque chanteur
			foreach($Ressh as $ShK=>$ShV)
			{
				$id_shk = $ShV['id_shk'];

	 // je cherche la duree de l'album
	$SelSil = 'SELECT SUM(album_duration) as totalAlbumDuration FROM `shk_album` WHERE idshk2 = "'.$id_shk.'"';
	//echo $SelSil.'<br />';
			
			
			$ReqSil = $connexion->query($SelSil);
			$ResSil = $ReqSil->fetchAll();
			//echo count($ResSil).'<br />';
			
			$totalD = '';
			
			foreach($ResSil as $SK=>$SV)
			{
				$totalD .= $SV['totalAlbumDuration'];
			}
			
			echo 'total est: '.$totalD.'<br />';
}
?>

SELECT id, MAX(album_duration) AS maxDuration FROM albums group by id ORDER BY MAX(album_duration) DESC LIMIT 1

select * from albums where album_duration= (SELECT  MAX(album_duration) AS maxDuration FROM albums)

SELECT id, MAX(album_duration) as maxDuration FROM albums ORDER BY MAX(album_duration) DESC LIMIT 1

id duree
1 20
2 30
3 15
4 32

j'ai mis le champs de album_duration en varchar, je pense pas que ca va me donner un bon resultat

SELECT id_al, MAX(album_duration) AS minDuration FROM albums ORDER BY album_duration ASC

SELECT id_al, MIN(album_duration) as minDuration FROM albums GROUP BY id_al ORDER BY album_duration ASC LIMIT 1';