default join in F.M is inner join while creating the
relation ship between tables . u can change that by editing
the join.   
Inner join is most widely used

The joins present in the reportnet are innerjoin and outer 
join. The most widely used join is inner join. Its a 
default join

Generally we have two types of joins here. 1.Inner 
join,2.outer join but widely  we are using inner join. 
Outer join is used for only when we need unmatched rows at 
the time we will go outer joins.

as all have set inner join is the default joing in 
Framework Manager , however  by generating the native sql 
from the report you can be able to manipulate the joins to 
cater for your condition