go - 使用 go 从我的 sqlite 数据库中获取最后一条记录

Question

我想查询我的 sqlite 数据库以获取我的书表中的最后一个 ID，然后插入最后一个 ID + 1 的数据。我是 Go 的新手，我不知道如何设置我的 lastid int 变量。任何帮助将不胜感激。

func getBookLastID() {

  var lastid int
  err := db.QueryRow("select max(id) from books").Scan(&lastid)
  fmt.Println(lastid)
  return (lastid + 1)
}

func insertBook(name, author string, pages int, publicationDate time.Time) (int, error) {
        //Create
        var bookID int

        var lastid int 
        lastid = getBookLastID()

        err := db.QueryRow(`INSERT INTO books(id, name, author, pages, publication_date) VALUES($1, $2, $3, $4, $5)`, lastid, name, author, pages, publicationDate).Scan(&bookID)

        if err != nil {
                return 0, err
        }

        fmt.Printf("Last inserted ID: %v\n", bookID)
        return bookID, err
}

Answer 1

我在函数中缺少“int”

错误:

func getBookLastID() {....

正确:

func getBookLastID() int {....

全部改正:

func getBookLastID() int { 

    var id int

    err := db.QueryRow("select ifnull(max(id), 0) as id from books").Scan(&id)
    if err != nil {
      panic(err)
    }
    fmt.Println("New record ID is:", id + 1)
    return id + 1
}

func insertBook(name, author string, pages int, publicationDate time.Time) (int, error) {
    //Create

    lastid := getBookLastID() 


    res, err := db.Exec(`INSERT INTO books(id, name, author, pages, publication_date) VALUES($1, $2, $3, $4, $5)`, lastid, name, author, pages, publicationDate)

    if err != nil {
        return 0, err
    }

    rowsCreated, err := res.RowsAffected()

        if err != nil {
        return 0, err
    }

    return int(rowsCreated), err

}