Crystal Reports Outer join with the concatenated fields

Message

     Hi, 

I really need your help. 

I am creating a SQL Command in crystal report. 

Says that I have 2 tables A and B and I want to join this two tables using left outer join. The field that need to join from table B have to concatenate. The SQL will be like this:- 

Select A.Field1, B.Field1 
from A left outer join B on (A.ID = B.ID1||B.ID2) 

 I tried to use (+) as an outer join instead of the word "left outer join" but it does not work. 
Somebody please lead me how to outer join with the concatenated fieds. 

Thanks 
Bee