How many teachers are there?
select count(*) from teachers
Show me the classroom of OTHA MOYER.
select classroom from teachers where firstname = "OTHA" and lastname = "MOYER"
What about classrooms other than that?
select distinct classroom from list where classroom not in select classroom from teachers where firstname = "OTHA" and lastname = "MOYER"
Give me the name of all first-grade students who are in any of those classrooms.
select distinct t1.firstname, t1.lastname from list as t1 join teachers as t2 on t1.classroom = t2.classroom where t1.grade = 1 except select t1.firstname, t1.lastname from list as t1 join teachers as t2 on t1.classroom = t2.classroom where t2.firstname = "OTHA" and t2.lastname = "MOYER"