左连接表与总和 - 导致问题

Question

我想要左连接多个表与两个总和列都加入中步表。

的表格看起来像：

表1

ID Value1 
1 3 
2 2 
3 3 

表2

ID Value1 
1 5 
2 2 
3 2 
4 1 

Jointable

ID 
1 
2 
3 
4 
5 
6 

我试图输出：

Table1Value1SUM Table2Value1Sum 
8 | 10 

随着SQL：

SELECT SUM(Table1.Value1) Table1Value1SUM,SUM(Table2.Value1) Table2Value1Sum From Table1 
Left Join JoinTable 
On JoinTable.ID = Table1.ID 
Left Join Table2 
On Table2.ID = Table1.ID 

我得到这些结果：

Table1Value1SUM Table2Value1Sum 
8 | 9 

Answer 1

jointable必须是在left join版与另外两张桌子。

SELECT SUM(Table1.Value1) Table1Value1SUM,SUM(Table2.Value1) Table2Value1Sum 
From JoinTable 
Left Join Table1 On JoinTable.ID = Table1.ID 
Left Join Table2 On JoinTable.ID = Table2.ID 

Answer 2

Left Join的Table2与JoinTable代替Table1

SELECT SUM(Table1.Value1) Table1Value1SUM,SUM(Table2.Value1) Table2Value1Sum From Table1 
Left Join JoinTable 
On JoinTable.ID = Table1.ID 
Left Join Table2 
On JoinTable.ID = Table2.ID 

Answer 3

有什么用jointable这来？你想Table 1和表2的总和，因此：

select 
    (select sum(value1) from table1) as table1sum, 
    (select sum(value1) from table2) as table2sum 

或

select t1.table1sum, t2.table2sum 
from 
    (select sum(value1) as table1sum from table1) t1 
cross join 
    (select sum(value1) as table2sum from table2) t2;