带有IN表达式的ORDER BY

Question

我想通过CustomerID订购，也想订购ORDER BY 2国家/地区，

我有

SELECT CustomerID, Country
FROM Customer
ORDER BY Country IN ("USA", "CANADA") ASC
ORDER BY Customer ID ASC;

应该返回

4, Canada
7, USA
8, USA
11, USA
12, Brazil
13, Belgium

Answer 1

在CASE子句中使用ORDER BY表达式：

SELECT CustomerID, Country
FROM Customer
ORDER BY
    CASE WHEN Country IN ("USA", "CANADA") THEN 0 ELSE 1 END,
    CustomerID;

这将首先将所有客户置于美国或加拿大，其次是来自所有其他国家/地区的客户。在这两组中的每一组中，记录将按CustomerID升序排序。