Determining variable counts

[saza]

I was asked 

1. How many character variables are there in the DEMOMED dataset?
2. What percent of subjects have hemophilia B (HTYPE)? (5 points) 
3. What is the latest date of registration (REG_DATE)?

and unsure if there is a way to do this in one code rather than manually counting or calculating. For number one I calculated 5 by hand looking at the variables but stuck on the last two bc sas says the dataset is too large?

proc freq data= DEMOMED ;

   where htype = 'Hemophilia B';

run;

[Kurt_Bremser · Accepted solution]

To do the first with code, query DICTIONARY.COLUMNS in PROC SQL.

For the second, try

proc freq data=demomed;
tables htype;
run;

For the third, see

proc sql;
select max(reg_date)
from demomed;
quit;