根据最大订单从2个不同的表中选择数据

Question

我需要从2个不同的表，产品和订单中选择数据，订单表将productid作为外键

我需要什么

我需要一个显示产品表中某些列的查询，具体取决于订单表中的最大订单数

我的努力

我尝试了以下查询

select sc_products.id, sc_products.name from sc_products, sc_orders where sc_orders.product = sc_products.id

问题

此查询只返回数据，并复制产品表中的ID 如

Full Texts          id  name
    Edit    Delete  9   3 Gold-Silver Elephants Rhinestone T Shirt
    Edit    Delete  9   3 Gold-Silver Elephants Rhinestone T Shirt
    Edit    Delete  9   3 Gold-Silver Elephants Rhinestone T Shirt
    Edit    Delete  9   3 Gold-Silver Elephants Rhinestone T Shirt
    Edit    Delete  9   3 Gold-Silver Elephants Rhinestone T Shirt
    Edit    Delete  9   3 Gold-Silver Elephants Rhinestone T Shirt
    Edit    Delete  9   3 Gold-Silver Elephants Rhinestone T Shirt
    Edit    Delete  9   3 Gold-Silver Elephants Rhinestone T Shirt
    Edit    Delete  9   3 Gold-Silver Elephants Rhinestone T Shirt
    Edit    Delete  9   3 Gold-Silver Elephants Rhinestone T Shirt
    Edit    Delete  9   3 Gold-Silver Elephants Rhinestone T Shirt
    Edit    Delete  9   3 Gold-Silver Elephants Rhinestone T Shirt
    Edit    Delete  9   3 Gold-Silver Elephants Rhinestone T Shirt
    Edit    Delete  9   3 Gold-Silver Elephants Rhinestone T Shirt
    Edit    Delete  9   3 Gold-Silver Elephants Rhinestone T Shirt
    Edit    Delete  9   3 Gold-Silver Elephants Rhinestone T Shirt
    Edit    Delete  9   3 Gold-Silver Elephants Rhinestone T Shirt
    Edit    Delete  9   3 Gold-Silver Elephants Rhinestone T Shirt
    Edit    Delete  9   3 Gold-Silver Elephants Rhinestone T Shirt
    Edit    Delete  9   3 Gold-Silver Elephants Rhinestone T Shirt
    Edit    Delete  9   3 Gold-Silver Elephants Rhinestone T Shirt
    Edit    Delete  9   3 Gold-Silver Elephants Rhinestone T Shirt
    Edit    Delete  9   3 Gold-Silver Elephants Rhinestone T Shirt
    Edit    Delete  9   3 Gold-Silver Elephants Rhinestone T Shirt
    Edit    Delete  10  Black-White Cats
    Edit    Delete  10  Black-White Cats
    Edit    Delete  4   Aquarius Rhinestone T Shirt
    Edit    Delete  4   Aquarius Rhinestone T Shirt
    Edit    Delete  249     Volleyball Mom Blue Rhinestone T Shirt
    Edit    Delete  249     Volleyball Mom Blue Rhinestone T Shirt

我的查询后显示上述结果，我只需要显示多次排序的记录，我需要count

更多关于我需要什么

我需要一个像

这样的结果

                            id  name                                        count
        Edit    Delete  9   3 Gold-Silver Elephants Rhinestone T Shirt   10
        Edit    Delete  10  product 2                                    15 

Answer 1

要完成此操作，您需要使用聚合函数COUNT。

我们提供GROUP BY以确保仅在唯一产品条目上进行计数。注意：scp.id足以满足此要求，但所有非聚合列必须包含在GROUP BY中。

最后，我们使用HAVING将结果限制为只有那些有多个订单的记录（即计数> 1）。

SELECT scp.id, scp.name, COUNT(sco.product)
FROM sc_products scp
INNER JOIN sc_orders sco ON scp.id = sco.product
GROUP BY scp.id, scp.name
HAVING COUNT(sco.product) > 1;

Answer 2

试试这个：

SELECT p.id, p.name, COUNT(o.id) orderCnt
FROM sc_products p 
INNER JOIN sc_orders o ON o.product = p.id
GROUP BY p.id HAVING COUNT(o.id) > 1
ORDER BY orderCnt DESC