confuse in joins in cognos.Why many ways for each type of join

[nsaxena]

Hi All ,
I have worked on database and have understanding of joins there.

Example : for inner join we use join table a ,table b on matching columns.

But in cognos how to define inner join :- i could see many options,hence got confused as in database inner joins is through only one syntax,but in cognos i could see different cardinality selection for same.
Example : table a(1:1) table b (1:1) is also inner join i saw,and table a(1:n) table b (1:n) is also join.
What is difference.Can some explain me with small example. 

Also for outer join i could see many combinations like :- 0..1<-->0..1 ,0..n<-->0..n

What is difference in all above case

Similarly for left outer join it is : table a( 0..n) and table b(1..n) > Left outer in table a.

I am confused that why we have so many combinations for each type of join and what is difference in each type of combination,as when compared to sql,we define in one shot each join.
Kindly help me in understanding this in cognos.

Many thanks in advance!!

[Lynn]

Please review the forum etiquette and do not double post. You've got the same question already on the Framework Manager board.

[nsaxena]

Hi Lynn

Sorry i was not aware of this.

This is my first post in FM section. I posted that in both in view of the fact that this issue is common to both report studio and FM and there might be viewers who only follow FM or report studio blogs.

[Lynn]

Hi Lynn

Sorry i was not aware of this.

This is my first post in FM section. I posted that in both in view of the fact that this issue is common to both report studio and FM and there might be viewers who only follow FM or report studio blogs.

A good strategy in cases like that would be to post a link to the original question explaining you want people on one board to be aware in case they can respond.