Grouping dates

[Pinkie Chambers]

Hello

I have a dataset with lots of repeated measures and dates. I currently have this in the long format

Patient ID . Chemotherapy date blood test date
a 1/5/19 29/4/19
a . 1/5/19

I am trying to group the blood test dates for the patients with the corresponding chemotherapy date. I have all the dates in STATA format. Then I want to understand how many tests typically a patient will have for each of their chemotherapy dates. I am really stuck as how to do this as I am fairly new to STATA.

Would be grateful for any advice or pointers!

[Mike Lacy]

Please take a look at the FAQ regarding how to use -dataex- to present example data. The data you have posted is not in a useful format for people to help you, and it's too small a sample to be useful for illustrating the substance of your situation. Beyond that, I think you will need to explain the basis on which you would like to "group" the blood test and chemotherapy dates: before? after? within a certain time period?