Select sum with joining table on gorm golang - go-gorm

Question

Let assume i have 3 model like this
type Violation struct{
ID uint `gorm:"primaryKey"`
ViolationName string
ViolationPoint int
}
type Student struct{
ID uint `gorm:"primaryKey"`
StudentName string
}
type ViolationRecord struct{
ID uint `gorm:"primaryKey"`
ViolationID int
V Violation `gorm:"constraint:OnUpdate:CASCADE,OnDelete:SET NULL;foreignKey:ViolationID;references:ID"`
StudentID int
S Student `gorm:"constraint:OnUpdate:CASCADE,OnDelete:SET NULL;foreignKey:StudentID;references:ID"`
RecordDate time.Time
}
Everything gonna be fine for CRUD system, but the new request is show total of the violation record/ student and sum the violation point.
i have try this
type ViolationSummary struct {
count int
sum int
}
func(s *Server) ShowSummary(id int){
var vs ViolationSummary
s.DB.Table("violation_records").
Select("count(violation_records.id) as count, sum(violations.violation_point) as sum").
Joins("left join violations on violation_records.violation_id=violations.id").Where("student_id = ?",id).Scan(&vs)
fmt.Println(vs.count)
fmt.Println(vs.sum)
}
but this function always show 0 value

Answer 1

I Have solve my problem with this code, i hope it can help.
func(s *Server) ShowSummary(id int){
vr:= []models.ViolationRecord{}
var total int64 = 0
var point int64 = 0
err:= s.DB.Where("student_id = ?",id).Preload(clause.Associations).Find(&vr).Error
if err != nil {
fmt.println("Error on load data")
}
for _, element := range vr {
total += 1
point += int64(element.V.ViolationPoint)
}
fmt.println(total)
fmt.println(point)
}