mysql - 基於多個id的多個表的總和列

Question

我有一個mySQL數據庫，有幾個相同的表。我需要加入所有表格，並且每次至少在2個表格中對id1和id2進行相等處理，然後總結觀點和點擊次數，如果不是，則只需顯示該行。

請參考下面的表格結構：

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 

最終的結果應該是如下表：

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 

我希望這是有道理的，有人可以用它幫助。

謝謝！

Answer 1

與工會把所有三個表的行在一起，然後組和像往常一樣：

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