UNION ALL 与 WHERE

UNION ALL 从客户和供应商表中选择所有（重复值）德国城市。这里 Country="Germany" 将在 where 子句中指定。

查询：

SELECT City, Country FROM Customers
WHERE Country='Germany'
UNION ALL
SELECT City, Country FROM Suppliers
WHERE Country='Germany'
ORDER BY City;

结果：

Number of Records: 14