问题描述
我有一张桌子,存储着一家本地商店的销售,除以销售类型和年份,再按客户名称分组(只有几个客户)。用户通过JavaScript传递了这些参数,我应该返回按销售类型分组的所选年份中的所有销售。
当前的sql语句返回当年属于第一类销售(即“一般”销售)的由不同客户分组的所有销售,但是我还想检索所选销售的哪个百分比属于每个用户的数量。
表格:
CREATE TABLE `sales` (
`id_sale` INT(11) NOT NULL,`name_of_client` VARCHAR(50) NOT NULL COLLATE 'latin1_swedish_ci',`type_of_sale` tinyint(1) NOT NULL,`year` YEAR NOT NULL,`amount` DOUBLE(22,0) NOT NULL,PRIMARY KEY (`id_sale`) USING BTREE
)
sql语句:
SELECT name_of_client,SUM(amount)
FROM sales
WHERE type_of_sale = 1 AND year = 2020
GROUP BY name_of_client
ORDER BY SUM(amount) DESC
我在SO线程中尝试了其他建议的解决方案,但它们计算表中所有销售额的百分比,我需要当年和当前销售额类型下每个客户的SUM(金额)百分比
解决方法
如果我理解正确,那只是条件聚合:
SELECT name_of_client,SUM(CASE WHEN type_of_sale = 1 THEN amount ELSE 0 END) / SUM(amount)
FROM sales
WHERE year = 2020
GROUP BY name_of_client
ORDER BY SUM(amount) DESC;
如果您希望每年这样做:
SELECT name_of_client,year,SUM(CASE WHEN type_of_sale = 1 THEN amount ELSE 0 END) / SUM(amount)
FROM sales
GROUP BY name_of_client,year
ORDER BY SUM(amount) DESC