What do you want to change?

Problem

When I need to use json_agg of PostgreSQL, it will be casted to an interface{}, so I tried to cast it to a custom struct type

-- -- name: GetRoomsGroupWithRooms :many
SELECT 
  sqlc.embed(rooms_groups),
  COALESCE(
    json_agg(rooms) FILTER (WHERE rooms.id IS NOT NULL),
    '[]'
  )::room[] AS rooms

I then added

        overrides:
         - db_type: "room"
            go_type:
              import: "github.com/me/mypkg/models"
              type: "Rooms"

It did generate the wanted struct

type GetRoomsGroupWithRooms struct {
	RoomsGroup RoomsGroup     `json:"rooms_group"`
	Rooms      []models.Rooms `json:"rooms"` // generated the proper type instead of []interface{}
}

But it did also include the ::room[] part in the generated query, which will cause an error in postgres

Proposed Solution

A macro sqlc.cast() that will do the type casting in the generated go struct, but not in the generated query?

-- -- name: GetRoomsGroupWithRooms :many
SELECT 
  sqlc.embed(rooms_groups),
  COALESCE(
    json_agg(rooms) FILTER (WHERE rooms.id IS NOT NULL),
    '[]'
  )::sqlc.cast(room[]) AS rooms

but the query won't include the ::sqlc.cast(room[]) part at all

What database engines need to be changed?

PostgreSQL

What programming language backends need to be changed?

Go