Self-join of a subquery
You can do so with WITH:
WITH subquery AS( SELECT * FROM TheTable) SELECT *FROM subquery q1JOIN subquery q2 on ...Or by creating a VIEW that contains the query, and joining on that:
SELECT *FROM TheView v1JOIN TheView v2 on ...Or the brute force approach: type the subquery twice:
SELECT *FROM ( SELECT * FROM TheTable) sub1LEFT JOIN ( SELECT * FROM TheTable) sub2 ON ...
Do you mean, the result of a query on a table, to that same table. If so, then Yes, it's possible... e.g.
--Bit of a contrived example but...SELECT * FROM TableINNER JOIN( SELECT UserID, Max(Login) as LastLogin FROM Table WHERE UserGroup = 'SomeGroup' GROUP BY UserID) fooON Table.UserID = Foo.UserID AND Table.Login = Foo.LastLogin
Yes, just alias the queries:
SELECT *FROM ( SELECT * FROM table ) t1JOIN ( SELECT * FROM table ) t2ON t1.column < t2.other_column