Join two structs on foreign key relation with jmoiron/sqlx (nested json object from struct)

nested_struct_join.go

/* 
Note: I have db.MapperFunc(FromCamelCaseToUnderScore)

This will make nested json like this

{
  "likes": [
    {
      "chat_id": 155636374,
      "created": "2018-08-04T10:52:36.360217Z",
      "from": {
        "id": 1,
        "rating": 11,
        "username": "anti1869"
      },
      "id": 21,
      "like_msg": "+",
      "question_msg": "",
      "reply_msg": "+",
      "to": {
        "id": 1,
        "rating": 11,
        "username": "anti1869"
      }
    }
  ]
}
*/

package web

import (
	"github.com/kataras/iris"
	"somewhere.com/somewhere/config"
	"log"
)

type LikeList struct {
	Likes		[]Like	`json:"likes"`
}

type Like struct {
	Id 			int		`json:"id"`
	ChatId		int64	`json:"chat_id"`
	Created		string	`json:"created"`
	LikeMsg		string	`json:"like_msg"`
	ReplyMsg	string	`json:"reply_msg"`
	QuestionMsg	string	`json:"question_msg"`
	From		User	`json:"from" db:"from"`
	To			User	`json:"to" db:"to"`
}

func GetLikeListhandler(ctx iris.Context){
	result := LikeList{}

	q := `	SELECT
				l.id, l.chat_id, l.created, l.like_msg, l.reply_msg,
				uf.id "from.id",
				uf.username "from.username",
				uf.rating "from.rating",
				ut.id "to.id",
				ut.username "to.username",
				ut.rating "to.rating"
			FROM likes l 
			JOIN users uf ON l.from_id = uf.id
			JOIN users ut ON l.to_id = ut.id 
			ORDER BY created DESC`

	rows, err := config.Db.Queryx(q)
	if err != nil {
		log.Fatal(err)
	}
	defer rows.Close()
	for rows.Next() {
		var l Like
		err = rows.StructScan(&l)
		if err != nil {
			log.Print(err)
		}

		result.Likes = append(result.Likes, l)
	}
	err = rows.Err()
	if err != nil {
		log.Panic(err)
	}

	ctx.JSON(result)
}

@anti1869 Thanks for putting this together. It helped me figure out an issue I was running into.

I know it's been awhile since you wrote this, but would you happen to remember what allows for the "from.id", "from.username", etc syntax in the SELECT query? Is it the standard database/sql package that is allowing for that syntax? Or is it some other package like lib/pq or jmoiron/sqlx?

I know this is years late, but it's just SQL. MySQL supports aliasing columns without using the AS keyword.