ah yes, my actual id column name is MMID. Forgot to change it back to ID after copy-pasting the code! Sorry

This is what I did:

SELECT lo.ID, lo.EndDate, MIN(hi.StartDate) AS StartDate

FROM Prescriptions lo

INNER JOIN Prescriptions hi

ON lo.ID = hi.ID

AND...

Yup..I sucessfully incorporated the patient ID and stuff and got the results I need. Thanks for following-up Jeff

Yes I did. Will try to follow the guidelines next time I post something 🙂

Thanks a lot for your help Jeff. A slight problem is that this doesn't include patientId in the join and I need to know which patients had the lapse..but this...