Slick notIn example

notin.scala

// This is the query to find all of a user's
// non-academy courses.  In other words...
// I want to list all of this user's courses, 
// but exclude courses associated with 
// academies in which this user is a member.

val user:User = ...

val excludeTheseAcademies = (for {
    au <- AcadUser if au.userId === user.id
  } yield au).map(_.acadId)
        
val courseQuery = for {
    cu <- CourseUser if cu.userId === user.id
    course <- Courses if course.id === cu.courseId
    if course.acadId notIn excludeTheseAcademies
  } yield course
  
// NOTE: Slick 2.1.0 removed notIn ... now you'd just do it like this:

val user:User = ...

val excludeTheseAcademies = (for {
    au <- AcadUser if au.userId === user.id
  } yield au).map(_.acadId)
        
val courseQuery = for {
    cu <- CourseUser if cu.userId === user.id
    course <- Courses if course.id === cu.courseId
    if !(course.acadId in excludeTheseAcademies)
  } yield course