获得一个城市的客户百分比

Question

我想检索居住在某些城市的注册客户的百分比。

目前我有这个

SELECT
COUNT(city) / Count(CustID) * 100 AS percent, city
FROM customer
GROUP BY City

目前每行提供100％的结果 我错过了一些明显的东西。如何修复查询？

Answer 1

您需要在单独的子查询中获取客户总数：

SELECT COUNT(city) / (SELECT Count(CustID) FROM Customer) * 100 AS percent, city
FROM customer
GROUP BY City

或使用CROSS JOIN：

SELECT
COUNT(city) / x.cnt * 100 AS percent, city
FROM customer
CROSS JOIN (SELECT Count(CustID) AS cnt FROM Customer) AS x
GROUP BY City

Answer 2

试试这个

SELECT
COUNT(city) / (SELECT Count(CustID) FROM Customer) * 100 AS percent, city
FROM customer c
GROUP BY City