I have a table of Sample Results. Each patient can have up to three records in this table. I differentiate them by using a variable called 'SampleType', which can be 1, 2 or 3. I also have a variable called 'HB' which holds a decimal value.
I want to subtract the HB value in SampleType = 1 from the HB value in SampleType = 3 for a particular patient. I can use a variable called 'SubjectNumber' to identify a patient.
Is there a way to perform this calculation?
Many thanks for any help.