Counting unique ID who taught a course in a given district and school

[Diana Serrano Amankwah]

Hi,
I imagine this question has already been answered but I cannot seem to find it. I want to figure out the number of teachers who taught a given course in a school and district. I have tried various different options, but none give me what I am looking for. Here is what I have tried:

egen N_Tpercourse = count(staffid), bysort (leanumber schoolnumber coursecode) /// this option counts the total number of times the staffid appears.
egen N_Tpercourse = gropu (staffid leanumber schoolnumber coursecode)

I have tried other things but none seem to do what I want them to do. Any suggestions? Or can you point me to where this question has already been answered? Thanks in advance.

[Hemanshu Kumar]

Maybe this, presuming you want to create a variable to track this count, for each combination of the variables leanumber schoolnumber coursecode

egen byte tag = tag(leanumber schoolnumber coursecode staffid)
egen N_Tpercourse = total(tag), by(leanumber schoolnumber coursecode)

If not, you may need to specify more carefully what you'd like, as well as supply a data example using dataex.

[Diana Serrano Amankwah]

Thank you Hemanshu, that did what I wanted it to do. I appreciate the help.