SQL：檢測兩個表之間的總和差異？

這似乎很簡單：我有兩張選票，我想看看哪些州有不同數量的選票。單獨來看，它很容易：SQL：檢測兩個表之間的總和差異？

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

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

如何查詢像state, votes_a, votes_b對於具有不同的結果狀態？

來源

2011-02-23 Philip Brocoum

？ – 2011-02-23 20:53:32

嘗試加入：

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，這將錯過其接受零票表的一個狀態。要解決這個問題，你可以使用FULL OUTER JOIN（假設你的數據庫支持這個功能）並檢查NULL。

來源

2011-02-23 20:48:18

這將給出如狀態，votes_a 狀態，votes_b 不是請求的狀態，votes_a，votes_b – Karl 2011-02-23 21:59:57

@Karl：現在修復，謝謝！ :) – 2011-02-23 22:06:57

嘗試......

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

您正在使用什麼數據庫

來源

2011-02-23 21:14:27 Karl

SQL：檢測兩個表之間的總和差異？

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