We have a transaction record that, for the sake of brevity, I will us
a simple paradigm to convey my need:

A sales clerk sells several pairs of shoes over the period of a day
each & every day the clerk works. Each transaction is recorded i
a database. All clerks use a single physical register but login t
capture unique ID. As each clerk logs in, it automatically logs ou
the prior user and writes a zero-dollar record

Each record logs the RcdNbr, clerk's ID, date-timestamp and sale
amount. (Other fields not pertinent to this discussion)

Example:
Rcd...CID...yyyy-mmdd.hhmm...Sal
001...ABC...2005-0101.0850...10.00
002...ABC...2005-0101.0930...00.00
003...DEF...2005-0101.1000...15.5
004...DEF...2005-0101.1200...00.0
005...ABC...2005-0101.1300...12.83
006...ABC...2005-0101.1530...00.0

The above is unsorted. I would first sort by CID (ClerkID) to get:

Rcd...CID...yyyy-mmdd.hhmm...Sal
001...ABC...2005-0101.0850...10.00
002...ABC...2005-0101.0930...00.00
005...ABC...2005-0101.1300...12.83
006...ABC...2005-0101.1530...00.0
003...DEF...2005-0101.1000...15.5
004...DEF...2005-0101.1200...00.0

As a double-check of a clerk's actual worked hours we want to extrac
the last record for each clerk for each day. In the above sample, I'
need records 004 & 006

The transaction file covers 6 months worth of data.

Is there a statement that I can construct that would extract the las
(greatest?) time for each clerk for each day