>Hi Fabio, thanks for the help.
>
>I am going to try out your examples and see which is best. will get back to you on that.
>
>What do you mean when you say ... "the density of the filter condition" ?

If the work table have 100000 record and
you have a
SET FILTER TO filterCondition
then:

COUNT TO nTotal
COUNT FOR filterCondition TO nFiltered
?m._nFiltered/m.nTotal && is the average density ( or filtering ratio )

The density of the filter condition is the the histogram of this ratio on the table splitted in small intervals:

* table = 100000 records
* split it into 1000 intervals of 100 records
compute 1000 ratios and put these into a histogram

>When you say ... "how many condition items (c1 and c2 and c3) are in OR", which OR do you refer to ?
>
>Thanks.

INLIST(Department+Section+Unit,cDepSecUnit1,cDepSecUnit2,...)
is

...;
(Department=Dep1 and Section=Sec1 and Unit=Unit1 );
OR
(Department=Dep2 and Section=Sec2 and Unit=Unit2 );
OR
...