RE: SQL record exists

[rob@xxxxxxxxx]

Thomas,

If one has an index built over the customer number, and the only thing 
read is the customer number then the entire table is not read, just the 
index.  For example, if I do this
select count(*), itemclass
from itemmaster
group by itemclass

and there is an index over the itemclass then the engine reads only the 
index and doesn't touch the physical file.

I believe that is true for a Primary or unique index built into the table 
as well.


Rob Berendt