Hello people.

Can you help with this problem I have been stuck on for quite a while now.

My data set consists of 2 columns: A - the points name (of which there is about 11)
B - date and time (DD/MM/YYYY HH:MM:SS) (should be every 15 minutes, multiples of 15: 00, 15, 30, 45)

the data set is a whole month

So, each point should have a date and time every 15 minutes, however, sometimes this does not happen. The minimum is that every point should have at least 1 reading every hour.
Is it possible to be able search the whole dataset and find which points do not have at least 1 reading every hour and if it doesn't return which point and the date and time?

Thanks guys, appreciated

example of data -
Point 1 31/03/2014 23:45
Point 1 31/03/2014 23:30
Point 1 29/03/2014 19:15
Point 1 29/03/2014 19:00
Point 1 18/03/2014 15:30
Point 1 18/03/2014 15:45
Point 1 08/03/2014 19:30
Point 1 08/03/2014 19:45
Point 1 08/03/2014 20:00
point 2 09/03/2014 14:30
point 2 09/03/2014 14:45
point 2 09/03/2014 15:00
point 2 09/03/2014 15:15
point 2 01/03/2014 02:15
point 2 01/03/2014 02:30
point 3 01/03/2014 03:30
point 3 01/03/2014 03:45
point 3 01/03/2014 04:00
point 3 01/03/2014 04:15
point 3 20/03/2014 22:30
point 3 20/03/2014 22:45