Finding the Latest Date from Multiple Date Fields


The following is a programming statement for transferring the latest date from
several date fields to one search date field.  For example, if your business 
application is a sales tracking database of all customer orders by date, you 
may need to know when a customer's last purchase was made.  If each order date 
is recorded in a different field, a search for the latest date in any of the 
fields would not give you the latest date for that customer order.  What you 
need to be able to do is compare all the dates on a customer order, find the 
latest date and put it in another field.

The following programming statement will perform this function.  You can also 
search for the highest or lowest number from multiple numeric fields.  The 
earliest date can also be retrieved using this program statement, by changing  
@MAX to @MIN.



From the Q&A Main Menu choose:


              File
              Design (choose your filename.dtf)
              Customize
              Program Form


Type the following in the appropriate date fields:


              Date1: >#1:#5=@MAX (#1..#3)

              Date2: >#2:#5=@MAX (#1..#3)

              Date3: >#3:#5=@MAX (#1..#3)

              Latest Date: #5 (This will be your search field)


To use this programming statement for more date fields, simply increase the 
underlined numbers by one for each additional date field, and increase #3 in 
the range (#1..#3) to the largest number of date fields you will be using.














Q & A Application Note       Rev. 6/92           #2202     Page 1 of 1