mysql - 基于多个id的多个表的总和列

Question

我有一个mySQL数据库，有几个相同的表。我需要加入所有表格，并且每次至少在2个表格中对id1和id2进行相等处理，然后总结观点和点击次数，如果不是，则只需显示该行。

请参考下面的表格结构：

Table1: 
id..id2...views...hits 
1...102...55......12 
2...103...12......22 

Table2: 
id..id2...views...hits 
1...123...512......13 
2...103...123......43 

Table3: 
id..id2...views...hits 
1...102...232......43 
2...103...100......70 

最终的结果应该是如下表：

id...id2...views...hits 
1....102...287....65 <-- This one is the result of adding 1st row of table1 and 2nd row of table 2 
1....123...512....13 <-- This is the 1st row of table2 as there's no other id2 = 123 
2....103...235....135 <-- This is the sum of 2nd row in table1 + 2nd row in table2 + 2nd row in table3 

我希望这是有道理的，有人可以用它帮助。

谢谢！

Answer 1

与工会把所有三个表的行在一起，然后组和像往常一样：

SELECT id, id2, SUM(views), SUM(hits) 
FROM 
(
    SELECT id, id2, views, hits 
    FROM Table1 
    UNION ALL 
    SELECT id, id2, views, hits 
    FROM Table2 
    UNION ALL 
    SELECT id, id2, views, hits 
    FROM Table3 
) x 
GROUP BY id, id2