mysql - 使用 MySQL 合并(或联合)两个结果集

Question

我有两个单独的 MySQL 查询，它们返回两组如下所示的结果

查询1结果:

country  | buyers | payment |  num_of_sales
UK       |   5    | 106.45  |    4
Thailand |   6    | 250.10  |    3

和:

查询2结果:

country | buyers | payment |  num_of_sales
UK      |   2    | 150.00  |    1
Norway  |   9    | 310.80  |    2

我需要的只是合并/联合它们，所以最终结果将如下所示:

预期结果

 country | buyers | payment |  num_of_sales
 UK      |   7    | 256.45  |    5
Thailand |   6    | 250.10  |    3
 Norway  |   9    | 310.80  |    2

请帮忙，如果可能的话，请提供一些解释。谢谢!

Answer 1

使用UNION ALL将两个查询结果集合并为一个结果集，然后使用GROUP BY Country和SUM得到您正在寻找的总计，如下所示:

SELECT
  country, 
  SUM(buyers) AS buyers, 
  SUM(payment) AS payment, 
  SUM(num_of_sales) AS num_of_sales
FROM
(  
   SELECT country, buyers, payment, num_of_sales
   FROM -- your query1 results
   UNION ALL
   SELECT country, buyers, payment, num_of_sales
   FROM -- your  query2 result2  
) AS t
GROUP BY country