MySQL使用group by在多个列上计数

我有一个包含以下列的数据库：

id (untique id)
product_matrix (Letter between A-Z to base priicing structre on)
sold (qty of that item sold)

如果我运行这个：

SELECT `product_matrix` as matrix, count(sold) as qty_sold FROM `products` WHERE `sold` > 0 group by `product_matrix`

我得到按产品矩阵分组的销售数量

我想得到的是：

矩阵（矩阵字母） 销售数量（按矩阵字母分组的销售项目计数） 产品（在该矩阵内销售的产品数量）

我该怎么做

SELECT `product_matrix` as matrix, 
        sum(sold) as qty_sold,
        count(id) as products
FROM `products` 
WHERE `sold` > 0 
group by `product_matrix`

SELECT `product_matrix` as matrix, 
        sum(sold) as qty_sold,
        count(id) as products
FROM `products` 
WHERE `sold` > 0 
group by `product_matrix`