Go 구조체에서 Null 허용 날짜/시간 열을 효율적으로 처리하려면 어떻게 해야 합니까?

type Reminder struct {
    Id         int
    CreatedAt  time.Time
    RemindedAt *time.Time
    SenderId   int
    ReceiverId int
}

type Reminder struct {
    Id         int
    CreatedAt  time.Time
    RemindedAt pq.NullTime // or sql.NullTime
    SenderId   int
    ReceiverId int
}

type NullTime struct {
    Time  time.Time
    Valid bool // Valid is true if Time is not NULL
}

row := db.QueryRow("...")
err := row.Scan(&id, &reminder.CreatedAt, &reminder.RemindedAt, &senderId, &receiverId)

if reminder.RemindedAt.Valid {
    // RemindedAt has a valid datetime value
} else {
    // RemindedAt is null
}