How to design tables - dabbler question
I have my ORDER
Every ORDER has ITEMS
Every ITEM has his VARIANTS
Every VARIANT has his QUANTITY

In general:
CREATE TABLE t_order (order_id INT AUTO_INCREMENT PRIMARY KEY, 
                      {other columns});

CREATE TABLE t_items (item_id INT AUTO_INCREMENT PRIMARY KEY, 
                      order_id INT REFERENCES t_order (order_id),
                      {other columns});

CREATE TABLE t_variants (variant_id INT AUTO_INCREMENT PRIMARY KEY, 
                         item_id INT REFERENCES t_items (item_id),
                         quantity DECIMAL(10, 2),
                         {other columns});