>>A 'nooptimize' option per clause expression is a good idea too.
>
>I don't like the NOOPTIMIZE option: what I am striving for (in many cases) is PARTIAL optimization. No R.Optimization would mean that ALL RECORDS have to be retrieved, whereas Full R.O. would mean (in some cases) retrieving almost all INDEX KEYS. With Partial R.O., both things can be avoided. In some cases, at least.

Here is what the SQL would like like with the nooptimize

Select * ;
    From D40 ;
    Where ;
       Left( D40Acct, 2 ) = "13" And ;
       Empty( D40CkNo ) NoOptimize
    Into Cursor qRailInvoices
<pre>
Here the Top clause uses the index because I have not placed a NoOptimize next to it.  The bottom clause has a NoOptimize.  As we have seen it is better not to use the index against the large set when you have a small set combined with a large set.

But you still can keep your index for a query like.
<pre>
Select * ;
    From D40 ;
    Where ;
       Empty( D40CkNo ) ;
    Into Cursor qRailInvoices

In this case, even though you are returning a large result set you want to use the index.