Excuse my ignorance? What is DMAX? I've never seen anything like that in
oracle.
Out of interest, In my oppinion the first suggestion, using a descending
index hint, the original poster had left out one important step. The order
by clause must be set to use the index in question descendingly... see the
INDEX_DESC hint in the Oracle 7 Performance Tuning guide.
In my experience, this is a very efficidnt way of solving the problem, with
a single indexed query, requires only one index fetch if the only value you
want is in the index, or one indexed table access otherwise. The catch is
that you must check that your explain-plan for your query is using the index
specified, and is not merge-sorting anything, since that can cause the
incorrect value to be returned. In this case use a USE_NL hint to ensure
nested loops.
Clint.
