MYSQL有2个表格。总共相同的日期。比较和减去日期

Question

​tablo1        tablo2 
--------------------------   ------------------------------ 
fiyat1   tarih1    fiyat2   tarih2 
----------  ------------  -----------  ----------- 
1200   03-2017    2100    03-2017 
1050   03-2017    5200    03-2017 
3250   04-2017    3200    04-2017 
2501   04-2017    
6100   05-2017 
1100   05-2017    

---

收集在同一日期在价格1，在2价， 减去2个总计，通过日期组收集在同一日期。

我想打印是这样的：

----------------------- 
05-2017  7200 
04-2017  2511 
03-2017  -5050 

的问题是真实的，但结果是错误的。我试过这个。

SELECT tablo1.tarih1, 
     tablo1.fiyat1, 
     SUM(tablo1.fiyat1), 
     tablo2.tarih2, 
     tablo2.fiyat2, 
     SUM(tablo1.fiyat1), 
     (SUM(tablo1.fiyat1) - SUM(tablo2.fiyat2)) AS sonuc 
FROM  tablo1 INNER JOIN 
     tablo2 ON tablo1.tarih1 = tablo2.tarih2 
GROUP BY tablo1.tarih1 

Answer 1

用表结构是因为它是可写的查询来获得期望的结果是：

SELECT t1.tarih1, (COALESCE(t1.fiyat1, 0) - COALESCE(t2.fiyat2, 0)) AS sonuc 
FROM 
    (SELECT tarih1, SUM(fiyat1) AS fiyat1 
     FROM tablo1 
    GROUP BY tarih1 
    ) AS t1 
    LEFT JOIN 
    (SELECT tarih2, SUM(fiyat2) AS fiyat2 
     FROM tablo2 
    GROUP BY tarih2 
    ) AS t2 
    ON t1.tarih1 = t2.tarih2 
ORDER BY t1.tarih1 DESC; 

不过，我想提供一些建议：

• 在MySQL date格式中存储日期通常是个好主意：YYYY-MM-DD。如果需要的话，运行年度报告会容易得多。
• 至于记账而言，也许你会发现以下是问答&一个是你的兴趣：What is a common way to save 'debit' and 'credit' information?