Using exists in subquery

[Sherzodbek-Muhammadiev]

java.lang.ClassCastException: class java.lang.Integer cannot be cast to class java.lang.Boolean (java.lang.Integer and java.lang.Boolean are in module java.base of loader 'bootstrap')

val isOpenSubQuery = StudentLessonEntity
                .slice(StudentLessonEntity.id)
                .select {
                (StudentLessonEntity.studentId eq studentId and
                        (StudentLessonEntity.courseId eq courseId) and
                        (StudentLessonEntity.lessonId eq LessonEntity.id))
            }


            val isOpen = exists(isOpenSubQuery).alias("is_open")

and I run query:

(CourseEntity innerJoin LessonPackageEntity innerJoin LessonEntity)
                .slice(LessonEntity.id, LessonEntity.name, isOpen, solvedCount, taskCount)
                .select { CourseEntity.id eq courseId }
                .map { Mapper.run { it.toStudentLessonData(solvedCount, taskCount, isOpen) } }

Mapper:

 fun ResultRow.toStudentLessonData(
        solvedCount: Expression<Int>,
        taskCount: Expression<Int>,
        isOpen: Expression<Boolean>,
    ) = StudentLessonData(
        id = this[LessonEntity.id].value,
        name = this[LessonEntity.name],
        solvedCount = this[solvedCount],
        taskCount = this[taskCount],
        isLocked = this[isOpen]
    )

And this line isLocked = this[isOpen] happened crash

[Sherzodbek-Muhammadiev]

Now, I am using my custom function exits2 as temporary solution:

class exists2(
    val query: AbstractQuery<*>
) : Op<Int>() {
    override fun toQueryBuilder(queryBuilder: QueryBuilder): Unit = queryBuilder {
        append("EXISTS (")
        query.prepareSQL(this)
        append(")")
    }
}