Go sql从扫描返回多行

Question

我正在使用 Postgresql 数据库。这是我要返回多行的代码块：

type NewsPaper struct {

    language string

    logo_url string

    slug string

    ranking string

    title string

    search_term string

}

func GetNewsPapers()  []byte{

    db := GetDB()

    newspaper := NewsPaper{}

    var json = jsoniter.ConfigCompatibleWithStandardLibrary

    rows, err := db.Query(`SELECT title, language, ranking, slug, search_term, logo_url FROM public.news_newspaper`)

    if err != nil {

        log.Println(err)

    }

    defer rows.Close()

    //results := []NewsPaper  // error : type []NewsPaper is not an expression

    for rows.Next() {

        err = rows.Scan(&newspaper.title, &newspaper.language, &newspaper.ranking, &newspaper.slug, &newspaper.search_term, &newspaper.logo_url)

        if err != nil {

            log.Println(err)

        }

        //results = append(results, newspaper)

    }

    fmt.Println(newspaper)  // printing last row

    err = rows.Err()

    if err != nil {

        panic(err)

    }

    values, _ := json.Marshal(newspaper)

    //fmt.Println(values)

    return values

}

问题是它从表中返回最后一行。我也尝试将结果存储在数组中，但我没有成功。

Answer 1

您为每一行设置相同的结构变量，这就是为什么您只获取最后一行信息。用于results := []NewsPaper{}创建空切片并为每一行创建新结构。这应该可行，我添加了一些评论。rows, err := db.Query(`SELECT title, language, ranking, slug, search_term, logo_url FROM public.news_newspaper`)if err != nil {    log.Println(err)}results := []NewsPaper{} // creating empty slicedefer rows.Close()for rows.Next() {    newspaper := NewsPaper{} // creating new struct for every row    err = rows.Scan(&newspaper.title, &newspaper.language, &newspaper.ranking, &newspaper.slug, &newspaper.search_term, &newspaper.logo_url)    if err != nil {        log.Println(err)    }    results = append(results, newspaper) // add new row information}fmt.Println(results)  // printing result

Answer 2

基本 CRUD 的另一种方法import (    "github.com/jmoiron/sqlx"    "context")type NewsPaper struct {    Language   string `json:"language" db:"language"`    LogoURL    string `json:"logo_url" db:"logo_url"`    Slug       string `json:"slug" db:"slug"`    Ranking    string `json:"ranking" db:"ranking"`    Title      string `json:"title" db:"title"`    SearchTerm string `json:"search_term" db:"search_term"`}type NewsPaperRepository interface {    List(ctx context.Context) ([]NewsPaper, error)}type newsPaperRepository struct {    db *sqlx.DB}func (r *newsPaperRepository) List(ctx context.Context) ([]NewsPaper, error) {    const selectQuery = `SELECT title, language, ranking, slug, search_term, logo_url FROM public.news_newspaper`    var newsPapers []NewsPaper    if err := r.db.SelectContext(ctx, &newsPapers, selectQuery); err != nil {        return nil, fmt.Errorf("news paper repository/problem while trying to retrieve news papers from database: %w", err)    }    return newsPapers, nil}