Re: Difference between Select and Omit in LF

>>so you are saying that the order of select/omit plays a role?

Precisely.  In his book, "Database Design and Programming for DB2/400", 
Paul Conte
explains it nicely:

"Because DB2/400 (now UDB for iSeries) steps through the select/omit 
specifications
in order and quits as soon as a condition is satisfied, you can improve 
the runtime
efficiency of select/omit specifications by putting the conditions that 
are most
likely to be matched towards the beginning of a series of multiple 
conditions ..."

So, your initial Omit specification is probably being matched by a much 
greater
number of records, (and hence the records are immediately excluded) than 
the 
corresponding Select condition.

The first Select condition is unmatched, so DB2 continues with the next 
Select
to seek a match - and still comes up empty for the vast majority of 
records.

Brian Parkins