> E.g. the non-equivalence operator is the same. MySQL will use indexes
> for "foo>0", but not "foo<>0", which ask for the same result (presumed
> foo is an unsigned column).
Perhaps I was a bit unclear... Using "foo > 0" does *NOT* use an index.
Using "foo > 0 AND foo < somevalue" *DOES* use an index.
> As Erv did not know why this could help: It uses a different operator
> than "IS NOT NULL", namely greather-than. One, that MySQL supports to
> make use of indexes.
Again, merely using greater than by itself produces results identical to
using IS NOT NULL.