从 MS Access 中的 2 个表中求和

Question

我需要编写一个 SQL 查询，根据每个表 (BrokerName) 中公共字段的分组，将两个不同表（保险和投资）中的字段 (BranchRevenue) 汇总为一个数字。数据库是 MS Access（我在下面的超链接中提供了一个示例结构）。

通过查看 SO 上的类似帖子，我的理解是，我需要定义各个表的总和（我可以这样做），然后使用 DISTINCT 或 DISTINCTROW 将它们聚合在一起（我不能这样做）。

这里是每个表的单独查询，它们正确地按 BrokerName 对 BranchRevenue 求和。

SELECT  Investments.BrokerName AS [BrokerName],Sum(Investments.BranchRevenue) as [BranchRevenue] 
FROM  Investments WHERE ( ((Investments.Ledger = 'Actual') AND (Investments.Year1 = 2017) AND (Investments.Period = 6) AND (Investments.Branch = 'Toronto') ) ) 
GROUP BY  Investments.BrokerName

SELECT  Insurance.BrokerName AS [BrokerName],Sum(Insurance.BranchRevenue) as [BranchRevenue] 
FROM  Insurance WHERE ( ((Insurance.Ledger = 'Actual') AND (Insurance.Year1 = 2017) 
    AND (Insurance.Period = 6) AND (Insurance.Branch = 'Toronto') ) ) 
GROUP BY  Insurance.BrokerName

如何使用单个 SQL 语句来完成此操作？

理想的解决方案是正确地将两个表中的 BranchRevenue 相加为每个 BrokerName 的一个数字，而不是从两个表中复制数据。

Answer 1

您可以在求和之前使用union all 将两个表的结果合并：

SELECT   [BrokerName], SUM([BranchRevenue])
FROM     (SELECT Investments.BrokerName AS [BrokerName],
                 Investments.BranchRevenue AS [BranchRevenue] 
          FROM   Investments 
          WHERE  Investments.Ledger = 'Actual' AND 
                 Investments.Year1 = 2017 AND 
                 Investments.Period = 6 AND 
                 Investments.Branch = 'Toronto'
          UNION ALL
          SELECT Insurance.BrokerName AS [BrokerName],
                 Insurance.BranchRevenue AS [BranchRevenue]
          FROM   Insurance
          WHERE  Insurance.Ledger = 'Actual' AND
                 Insurance.Year1 = 2017 AND
                 Insurance.Period = 6 AND
                 Insurance.Branch = 'Toronto'
         ) t
GROUP BY [BrokerName]

Answer 2

你可以做一个简单的联合所有查询然后分组

select BrokerName, sum(BranchRevenue) from (
select * from Insurer
  where...
union all
select * from Investments
  where ...)
group by BrokerName