calculating time differences

[Anonymous]

I need to calculate the time differences between the dispensing of any two subsequent prescriptions.  The following table illustrates the situation:

ScriptNumber	DateTImeDispensed
161797	30/01/15 18:29
161798	30/01/15 18:45
161798	30/01/15 18:45
161798	30/01/15 18:45
161799	30/01/15 18:49
161800	31/01/15 08:18
161800	31/01/15 08:18
161801	31/01/15 08:39
165073	27/03/15 07:44
161802	31/01/15 09:14
161803	31/01/15 09:38
161804	31/01/15 09:41
161804	31/01/15 09:41
161804	31/01/15 09:41
161805	31/01/15 09:48
161806	31/01/15 09:55
161806	31/01/15 09:55
161806	31/01/15 09:55
161807	31/01/15 10:03
161808	31/01/15 10:19
161809	31/01/15 10:21
161810	31/01/15 10:22
161810	31/01/15 10:22
161811	31/01/15 10:28
161811	31/01/15 10:28

The ScriptNumber is a unique identifier of a prescription.  How do i calculate the time difference between any two prescriptions?

[Anonymous]

Many thanks Petter, changing expression worked.  How can i show the average time difference?

Regards

[Anonymous]

Many thanks Massimo, comments noted.

Regards

[pratap6699]

show me the all expressions dispences,days also

[petter]

You can add a measure with the expression:

  Avg(DateTimeDispensed) and label it AvgDisp

Then one more expression like this:

  AvgDisp-Above(AvgDisp)

If you want it compared to the average of all then use:

Avg(TOTAL DateTimeDispensed)