(Wait )Time Calculations

  • Thread starter Thread starter Van W
  • Start date Start date
V

Van W

I'm trying to do simple calculations with the data type
Date/Time and I'm running into all types of problems. I
hoped this would be a simple database to calculate wait
times for patients. A start time and end time are entered
as a record. The data types were Date/Time with a format
of Short Time. A calculated field (Wait Time) finds the
difference by subtrating start time from end time. How do
a find Sums or Averages of wait time? Do these functions
only work with numeric values. Is there a conversion
function I can use. I can't find any information of doing
calculations with a time value. I tried the Avg() and Sum
() functions in the report but only received an error. Are
there no functions that do calculations of time.Any help
would be appreciated.
Thanks, Van
 
In ACCESS, dates and times are stored as a decimal number. The integer part
is the number of days since December 31, 1899. The decimal part is the
fraction of a day represented by the time (based on 24-hour day).

Thus, for example, 5 AM on January 1, 2003 is this number:
37622.2083333333

The way to calculate time differences is to use the DateDiff function to get
the time difference; it's best to do this in minutes and then manipulate the
result into the desired units. For example, if you want the time difference
in minutes between 5 AM and 11 AM on January 1, 2003, you'd use this
expression:
DateDiff("n", #1/1/2003 5 AM#, #1/1/2003 11 AM#)

You then can convert the number of minutes to hours, days, etc.
 
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