join_ids.go

package main

import (
  "fmt"
  "strings"
)

type model struct {
	ID int
}

func joinIds(models []model) string {
	ids := make([]string, len(models))
	for i := 0; i < len(models); i++ {
		ids[i] = fmt.Sprint(models[i].id)
	}
	return strings.Join(models, ",")
}

func run() {
	models := []model{}
	query := "SELECT id FROM blah WHERE id in (%s)"
	rows, err:= db.Query(fmt.Sprintf(query, joinIds(models))
	...
	...
}