遇到問題: 我想要當$articles是空的時候會列印全部(成功)，當我$articles有值時又會篩選資料(錯誤:這邊會變成直接跳錯) 請問我要怎麼改

錯誤訊息: (article like '%$articles%') 這行
Warning: sprintf(): Too few arguments in C:\xampp\htdocs\xampp\index_2.php on line 13

我的想法: (沒資料)模糊收尋全出來，(有資料)依照條件出。

程式碼:

$user=isset($_POST['S1'])<>NULL?$_POST['S1']:"";	
$articles=isset($_POST['S2'])<>NULL?$_POST['S2']:"";	
$sql=sprintf(
"SELECT part_number.id,part_number.product_name,part_number.specification,
part_number.selling_price,part_number.operations_center,
part_number.inventory,part_number.pictuture_id,part_number.picture,
CASE WHEN app_shop_favorite.user_id = '$user' 
THEN 'Y' ELSE '' 
END ANS
FROM part_number 
LEFT JOIN app_shop_favorite ON app_shop_favorite.part_no = part_number.id 
where status='F' 
AND (article  like '%$articles%')
order by part_number.pictuture_id desc ");