pslname,sfname, snumber(student |X|ststudent=snumber ( sstdatepassed is not null(studying)) |X| 1.ststudent = 2.ststudent and 1.stcourse != 2.stcourse ( sstdatepassed is not null(studying )))Pairs of passed studies with a common student and a different course are constructed and then joined with student record.