Databases Reference
In-Depth Information
Even in the previous case we can see the substantial equivalence of the
NOT
IN
and
NOT
EXISTS
operations, related to gets/reads.
In step 6, we do a transformation to the query, using an algebraic expression equivalent to
the intersection of two sets:
A ∩ B = A - (A - B)
So we have:
A - B = A - (A ∩ B)
