Kelompokkan menurut id yang memiliki max(date_field)

Di sini, Anda harus memiliki subquery yang mendapatkan date_add terbaru untuk setiap id_order di atas tabel ps_order_history . Hasil subquery tersebut kemudian digabungkan kembali pada tabel asli ps_order_history asalkan cocok dengan dua kolom:date_add dan id_order .

SELECT  c.firstname, 
        c.lastname, 
        d.product_name, 
        o.payment, 
        s.name, 
        h.date_add
FROM    ps_orders o
        INNER JOIN ps_order_detail d ON d.id_order = o.id_order
        INNER JOIN ps_customer c ON c.id_customer = o.id_customer
        INNER JOIN ps_order_history h ON o.id_order = h.id_order
        INNER JOIN  
        (
            SELECT  id_order, MAX(date_add) max_date
            FROM    ps_order_history
            GROUP   BY id_order
        ) x ON  h.id_order = x.id_order AND
                h.date_add = x.max_date
        INNER JOIN ps_order_state_lang s ON s.id_order_state = h.id_order_state
WHERE   s.id_lang =6
GROUP   BY c.id_customer