With Update From ... vs. Update ... From (With)

["David G. Johnston" <david.g.johnston@xxxxxxxxx>]

Hello!

Is there any non-functional difference between these two forms of Update?

WITH name AS ( SELECT )

UPDATE tbl SET ...

FROM name

WHERE tbl.id = name.id

and

UPDATE tbl SET ...

FROM ( WITH qry AS ( SELECT ) SELECT * FROM qry ) AS name

WHERE tbl.id = name.id

They both better give the same results but does the backend treat them differently?

Does the answer to my question depend on the version of PostgreSQL?

Thanks!

David J.