Updating using extra in related query

[rajumb502]

Refer: #413

Context:
I have a many to many relation between subjects and assessments through a mapping table class_subjects_assessments. The class_subjects_assessments table has a bunch of extra fields and I would like to update a specific relation specified by one of the extra fields csa_id using $relatedQuery():

                await subject
                    .$relatedQuery('assessments', tx)
                    .where('csa_id','=', csaId)
                    .patch({
                      state: status,
                      completed_questions: completedQuestions
                    });

The above generates the sql:

                update "class_subjects_assessments" set "state" = ?, "completed_questions" = ? 
                where 
                  "class_subjects_assessments"."assessment_id" in 
                    (
                      select "assessments"."id" 
                      from "assessments" inner join "class_subjects_assessments" 
                        on "assessments"."id" = "class_subjects_assessments"."assessment_id" 
                      where "class_subjects_assessments"."subject_id" in (?) 
                        and "csa_id" = ?
                    ) 
                  and "class_subjects_assessments"."subject_id" in (?)

However, what I required was this:

                update "class_subjects_assessments" set "state" = ?, "completed_questions" = ? 
                where 
                  "class_subjects_assessments"."assessment_id" in 
                    (
                      select "assessments"."id" 
                      from "assessments" inner join "class_subjects_assessments" 
                        on "assessments"."id" = "class_subjects_assessments"."assessment_id" 
                      where "class_subjects_assessments"."subject_id" in (?) 
                        and "csa_id" = ?
                    ) 
                  and "class_subjects_assessments"."subject_id" in (?)
                  and "csa_id" = ?  ---- <- NOTE

The first query ends up updating all the records where assessment_id and subject_id match, which is not what I required.

For now, I created a model for class_subjects_assessments as a workaround. Is there any way to use $relatedQuery for my requirement without creating this model?

Packages:
"graphql": "16.8.1",
"graphql-yoga": "4.0.3",
"knex": "2.5.1",
"objection": "3.1.2",
"pg": "8.11.3",