SQL：检测两个表之间的总和差异？

这似乎很简单：我有两张选票，我想看看哪些州有不同数量的选票。单独来看，它很容易：SQL：检测两个表之间的总和差异？

select state, sum(votes) from votes_a group by state; 

select state, sum(votes) from votes_b group by state;

如何查询像state, votes_a, votes_b对于具有不同的结果状态？

来源

2011-02-23 Philip Brocoum

？ – 2011-02-23 20:53:32

尝试加入：

SELECT 
    totals_a.state, 
    totals_a.total_votes, 
    totals_b.total_votes 
FROM 
(
    SELECT state, SUM(votes) AS total_votes 
    FROM votes_a 
    GROUP BY state 
) AS totals_a 
JOIN 
(
    SELECT state, SUM(votes) AS total_votes 
    FROM votes_b 
    GROUP BY state 
) AS totals_b 
ON totals_a.state = totals_b.state 
WHERE totals_a.total_votes <> totals_b.total_votes

注意，这将错过其接受零票表的一个状态。要解决这个问题，你可以使用FULL OUTER JOIN（假设你的数据库支持这个功能）并检查NULL。

来源

2011-02-23 20:48:18

这将给出如状态，votes_a 状态，votes_b 不是请求的状态，votes_a，votes_b – Karl 2011-02-23 21:59:57

@Karl：现在修复，谢谢！ :) – 2011-02-23 22:06:57

尝试......

select state, sum(votes_a), sum(votes_b) 
from (select state, sum(votes) votes_a, 0 votes_b 
     from votes_a 
     group by state) tbl_a 
    (select state, 0 votes_a, sum(votes) votes_b 
     from votes_b 
     group by state) tbl_b 
where tbl_a.state = tbl_b.state 
group by state

您正在使用什么数据库

来源

2011-02-23 21:14:27 Karl

SQL：检测两个表之间的总和差异？

回答

相关问题