Calculating a Time Span Across Midnight 
          Scenario:  Employees  working third  shift at  a manufacturing  plant
          start work  at 11:30  p.m. and  end their  workday at  7:45 a.m.  the
          following morning. Subtracting their starting time from their  ending
          time produces an incorrect  value. For  example, a  starting time  of
          11:30 p.m. and an ending  time of  7:45 a.m.  produces the  incorrect
          value 15:45. With the formula below, Superbase calculates differently
          depending on whether or not  the starting  time is  greater than  the
          ending time. 
          File definition: 
               Filename: TIME24HR       
                    StartTime           hh:mm am       
                    EndTime             hh:mm am       
                    TimeDifference CLC RDO   hh:mm

          Sample record:      
                    StartTime      11:00 pm 
                    EndTime        7:00 am                           
     TimeDifference 8:00 {Calculated result*}          

          *TimeDifference read-only calculation formula
          IF  (  EndTime.TIME24HR  <  StartTime.TIME24HR  ,  (  86400000  -   (
          StartTime.TIME24HR  -  EndTime.TIME24HR  )  )  ,  EndTime.TIME24HR  -
          StartTime.TIME24HR )
          Formula explanation
          If the EndTime is less than the StartTime then subtract the StartTime
          from  the  EndTime  and  subtract  that  difference  from   86400000,
          otherwise subtract the StartTime from the EndTime. The value 86400000
          is the number of thousandths of a second in 24 hours  (one minute  is
          60,000 thousandths of a second.)
          Manual references
               Designing Files, pg. 2-5, "Modifying a file definition"
               Designing Files, pg. 5-15, "Working with time display formats"
               Designing Files, pg. 6-1, "Using formulas"
               SBL Reference, pg. 3-6, "Date and time" 
               SBL Reference, pg. 4-201, "IF"
               SBL Reference, pg. 4-457, "TIMEVAL" 



                                        















Program:  Superbase      
Versions: 2.0
Date:     March 29, 1994      
D
Date: