SQLnewcommer
Technical User
Hello,
I have reading about queries involving more than two tables. But I am still confused.
Suppose I have 5 tables A,B,C, D and Q
I have already joined A,B,C,D. Q can be joined to A, B or C ( has their foreign keys) . How do I decide whether to join Q to A,B or C?
Similarly, will the way in which tables are joined affect the result?
I have joined A->B, A->C, A->D and A->Q
I can also join as C->B, C->A B->D Q->A
The keys permit the following orders. How do I know which way to join? What are the things I need to take into consideration while writing the join criteria???
I have reading about queries involving more than two tables. But I am still confused.
Suppose I have 5 tables A,B,C, D and Q
I have already joined A,B,C,D. Q can be joined to A, B or C ( has their foreign keys) . How do I decide whether to join Q to A,B or C?
Similarly, will the way in which tables are joined affect the result?
I have joined A->B, A->C, A->D and A->Q
I can also join as C->B, C->A B->D Q->A
The keys permit the following orders. How do I know which way to join? What are the things I need to take into consideration while writing the join criteria???
