Mysql request problem

Thank you for your help.
I have reconsidered all my request and now it is working properly. That's what I did as a request:

Code:

SELECT products.id, products.reference, products.label, products.category, products.image, stocks.id_warehouse, (SUM(CASE WHEN slug IN ('orders', 'variation', 'transfer', 'add') THEN stocks.qty ELSE 0 END) - SUM(CASE WHEN slug ='used' THEN stocks.qty ELSE 0 END)) as qty, SUM(CASE WHEN stocks_alert.id_product = stocks.id_product  THEN stocks_alert.qty_alert ELSE 0 END) as qty_alert FROM products LEFT JOIN stocks ON stocks.id_product = products.id LEFT JOIN stocks_alert ON stcks_alert.id_warehouse = stocks.id_warehouse WHERE (products.reference LIKE '%%'  ESCAPE '!' OR  products.label LIKE '%%' ESCAPE '!') GROUP BY products.id HAVING (`qty` < `qty_alert`)