Subject Circular join question
Author Rick DeBay
I have a circular relationship:

Top_Entity1 <-- Entity_Group <-- Entity1_Entity2_Link
^ |
| |
| V
Child <-- Child_Entity2_Link <-- Top_Entity2

To get the information I need, there are at least five joins.
I don't know if I should add a sixth join to close the circle, or a
where clause to do it.
For example, given that all other parts of the SQL consist of joins,
should I finish with

JOIN Child_Entity2_Link a ON a.Top_Entity2 = Top_Entity2.ID


WHERE Child_Entity2_Link.Top_Entity2 = Top_Entity2.ID

I ask because Child_Entity2_Link is what started the join statements,

FROM Child_Entity2_Link JOIN Top_Entity1 ON ...

and I don't know if it is correct to have the join closed like that, or
a burden on the engine.

Rick DeBay
Senior Software Developer