Beego, unable to query many to many relation field

Question

I have the following models:

type User struct {
    ID                       int64               `orm:"pk;auto;column(id)" json:"id"`
    FirstName                *string             `json:"first_name"`
    LastName                 *string             `json:"last_name" orm:"null"`
    FullName                 *string             `json:"full_name"`
    Posts                    []*Post             `orm:"rel(m2m);rel_through(demo/db/models.UserPosts)" json:"posts"`
}

and

type UserPosts struct {
    ID         int64   `orm:"pk;auto;column(id)" json:"id"`
    Post       *Post   `orm:"rel(fk);column(post_id)" json:"post"`
    User       *User   `orm:"rel(fk);column(users_id)" json:"user"`
    CreatedAt  int64   `json:"created_at"`
    UpdatedAt  int64   `json:"updated_at"`
    IsInactive bool    `json:"is_inactive"`
}

and

type Post struct {
    ID         int64   `orm:"pk;auto;column(id)" json:"id"`
    Content    *string `json:"content"`
    Type       *string `json:"type" orm:"null"`
    CreatedAt  int64   `json:"created_at"`
    UpdatedAt  int64   `json:"updated_at"`
    IsInactive bool    `json:"is_inactive"`
    Users      []*User `orm:"reverse(many)" json:"users"`
}

I want to order the distinct users queried via the created_at field of the Post table.

But whenever I run the following query

import "github.com/astaxie/beego/orm"

db := orm.NewOrm()
qs := db.QueryTable(new(models.User))
num, err := qs.Distinct().RelatedSel().All(&users)

The query formed by beego does not contain the field created_at of Post table and hence it gives an error. The query for the same is listed below:

SELECT DISTINCT T0."id", T0."first_name", T0."last_name", T0."full_name"
FROM "users" T0 
INNER JOIN "user_posts" T1 
    ON T1."users_id" = T0."id" 
WHERE T1."tenants_id" 
    IN $1 
    AND T1."is_inactive" = $2 
ORDER BY T1."created_at" DESC ;

I checked through the documentation but wasn't able to find any hint to the solution.

NOTE: The disctinct is required due to other constraints I have in my code which I have not highlighted in the question since that is out of scope

Hoping someone can point me in the right direction to achieve the same.