Question

我有按城市销售的产品如何退回城市销售的最大产品？

这是我的疑问：

我将每种产品的数量总和设为单个产品数量值。

select
product,
sum(qty_city_o) as qty_o,
sum(qty_city_t) as qty_t,
sum(qty_city_th) as qty_th
FROM products
GROUP BY product

Answer 1

您必须为每个城市执行单独查询。类似的东西：

SELECT qty_city_o, COUNT(product) FROM products GROUP BY qty_city_o ORDER BY COUNT(product) DESC LIMIT 1

Answer 2

这应该为您提供每个城市的最大销售产品：

SELECT 'city_o', A.* FROM (SELECT 
    product, productcount
FROM
    (SELECT 
        product, COUNT(product) productcount
    FROM
        products
    WHERE
        qty_city_o > 0
    GROUP BY product) B
ORDER BY productcount DESC
LIMIT 1 ) A
UNION ALL
SELECT 'city_t', A.* FROM (SELECT 
    product, productcount
FROM
    (SELECT 
        product, COUNT(product) productcount
    FROM
        products
    WHERE
        qty_city_t > 0
    GROUP BY product) B
ORDER BY productcount DESC
LIMIT 1 ) A
UNION ALL
SELECT 'city_th', A.* FROM (SELECT 
    product, productcount
FROM
    (SELECT 
        product, COUNT(product) productcount
    FROM
        products
    WHERE
        qty_city_th > 0
    GROUP BY product) B
ORDER BY productcount DESC
LIMIT 1) A;

我怎样才能归还城市出售的最大产品？

2 个答案: