Question

I am using mysql.

I have two tables

Students:
stud_num 
prof1
prof2

Prof
prof_id
first_name
last_name

Prof Id is a foreign key in the students table.

I want to get the stud_num and prof1 as first and last name and prof2 as first and last name

Here is my query that doesn’t work:

select s.stud_num, CONCAT(p.first_name, " ", p.last_name) as PROF1, CONCAT(p.first_name, " ", p.last_name) as PROF2
from students s
inner join prof p
on s.prof1 = p.prof
and s.prof2 = p.prof

This does not work. Is there an easy way to do this???

Answer 1

Join TWICE to the professors table, but I would suggest LEFT join in case one of the professor’s IDs is not provided

select 
      s.stud_num, 
      CONCAT(p1.first_name, " ", p1.last_name) as PROF1, 
      CONCAT(p2.first_name, " ", p2.last_name) as PROF2
   from 
      students s
         LEFT join prof p1
            on s.prof1 = p1.prof
         LEFT join prof p2
            on s.prof2 = p2.prof