我正在尝试加入下表：
表a：

Type1   Type2   ID  Object  Location
Sample  Dummy   1   X111    111222
Sample  Dummy   2   X333    333444
Sample  Dummy   2   X333    555666
Sample  Red     1   X222    666777
Test    Red     1   X222    666777
Test    Red     1   X222    666777

表b：

Source  Type2   ID  Object  Logged
SR1     Dummy   1   X111    17
SR1     Dummy   2   X333    1
SR1     Red     1   X222    12
SR2     Dummy   1   X111    9
SR2     Dummy   2   X333    9
SR2     Red     1   X222    20

我的sql代码：

SELECT B.Source, B.Type2, B.ID, B.Object, B.Logged, A.Location 
FROM A RIGHT JOIN B ON 
    A.Type1='Sample' AND 
    A.Type2=B.Type2 AND 
    A.ID=B.ID AND 
    A.Object=B.Object 
WHERE B.Source='SR2'

我期待以下结果：

Source  Type2   ID  Object  Logged  Location
SR1     Dummy   1   X111    17      111222
SR1     Dummy   2   X333    1       333444
SR1     Dummy   2   X333    1       555666
SR1     Red     1   X222    12      666777

但我得到的却是：

Source  Type2   ID  Object  Logged  Location
SR1     Dummy   1   X111    17      111222
SR1     Dummy   2   X333    1       -
SR1     Dummy   2   X333    1       -
SR1     Red     1   X222    12      666777

我的代码怎么了？请帮忙。