ERROR: missing FROM-clause entry for table when using GORM - postgresql

Question

These are the tables in my database
CREATE TABLE vehicles
(
id VARCHAR PRIMARY KEY,
make VARCHAR NOT NULL,
model VARCHAR NOT NULL,
)
CREATE TABLE collisions
(
id VARCHAR PRIMARY KEY,
longitude FLOAT NOT NULL,
latitude FLOAT NOT NULL,
)
CREATE TABLE vehicle_collisions
(
vehicle_id VARCHAR NOT NULL,
collision_id VARCHAR NOT NULL,
PRIMARY KEY (vehicle_id, collision_id)
)
So i need to find list of vehicles with a particular collision_id. I am using gorm .
I tried to implement it in a way
var vehicles []entities.Vehicles
err := r.db.Joins("JOIN vehicles as vh on vh.id=vehicle_collisions.vehicle_id").Where("vehicle_collisions.collision_id=?",
id).Find(&vehicles).Error
if err != nil {
fmt.Println(err)
}
But it is throwing me error
ERROR: missing FROM-clause entry for table "vehicle_collisions" (SQLSTATE 42P01)
Any help would really be appreciated.

Answer 1

Thank you mkopriva as pointed
when you pass &vehicles which is []entities.Vehicles to Find the query generated would be as below:
SELECT
*
FROM
vehicles
JOIN
vehicles vh
ON vh.id = vehicle_collisions.vehicle_id
WHERE vehicle_collisions.collision_id=1
which won't be correct to solve the problem modify the query as:
err := r.db.
Joins("JOIN vehicle_collisions AS vc ON vc.vehicle_id=vehicles.id").
Where("vc.collision_id = ?", id).
Find(&vehicles).Error

Answer 2

As the question lacks some details, I tried to guess them. I hope that the answer provided is relevant to you! Let me present the code that is working on my side:
package main
import (
"gorm.io/driver/postgres"
"gorm.io/gorm"
_ "github.com/lib/pq"
)
type Vehicle struct {
Id string
Make string
Model string
Collisions []Collision `gorm:"many2many:vehicle_collisions"`
}
type Collision struct {
Id string
Longitude float64
Latitude float64
}
func main() {
dsn := "host=localhost user=postgres password=postgres dbname=postgres port=5432 sslmode=disable"
db, err := gorm.Open(postgres.Open(dsn), &gorm.Config{})
if err != nil {
panic(err)
}
db.AutoMigrate(&Vehicle{})
db.AutoMigrate(&Collision{})
// add dummy data to the db
collision := &Collision{"1", 4.4, 4.5}
db.Create(collision)
db.Create(&Collision{"2", 1.1, 1.5})
db.Create(&Vehicle{Id: "1", Make: "ford", Model: "fiesta", Collisions: []Collision{*collision}})
db.Create(&Vehicle{Id: "2", Make: "fiat", Model: "punto", Collisions: []Collision{*collision}})
// get all vehicles for collision 1
var vehicles []Vehicle
db.Debug().Joins("inner join vehicle_collisions vc on vehicles.id = vc.vehicle_id").Find(&vehicles, "vc.collision_id = ?", "1")
}
The code starts with the structs' definitions.
Please note the Gorm annotation on the field Collisions.
After adding some data, the query should be pretty straightforward: we use the Joins method to load data from the table vehicle_collisions and in the Find method we filter out only records with collision_id equal to "1".
Let me know if this helps you or you need something else!