Don't think of p1 and p2 as the "same" table. They are two separate
and distinct instances of empl. They are linked in the conditions, but
they are just like two totally separate tables with identical sets.
The first example says that p1 is the table of employees named 'fred',
and p2 is employees with an lft greater than or equal to fred's lft, and
less than or equal to fred's rgt.
That's different from example two, where logically, p2 is a query of
employees named fred, and p1 is a query of employees with an lft
LESS THAN or equal to Fred's lft and also GREATER THAN or equal
to fred's rgt.
Bill
On Fri, 24 Aug 2001 19:57:20 +0100, Ben Petersen wrote:
>They are correct, but I don't get it, as p1 and p2 are the same
>table, and the only difference in the queries is
