drrqwokuz71031449 2016-06-14 16:36
浏览 303

Golang-为什么SQL占位符不起作用?

My code is as follow (I use gorm):

e.GET("/search", func(c echo.Context) error {
    keyword := c.QueryParam("keyword")

    results := make([]searchResult, 0)
    if keyword != "" {
        db, err := models.ConnectDB()
        defer db.Close()
        if err != nil {
            return err
        }

        rows, err := db.Raw("SELECT songs.name, singers.name, albums.name FROM songs, singers, albums WHERE (songs.singer_id = singers.id AND songs.album_id = albums.id) AND (songs.name LIKE '%?%' OR singers.name LIKE '%?%' OR albums.name LIKE '%?%')", keyword, keyword, keyword).Rows()
        defer rows.Close()

        var songName, singerName, albumName string
        if err == nil {
            for rows.Next() {
                rows.Scan(&songName, &singerName, &albumName)
                results = append(results, searchResult{
                    SongName:   songName,
                    SingerName: singerName,
                    AlbumName:  albumName,
                })
            }
        } else {
            return err
        }
    }
    return c.Render(http.StatusOK, "search", results)
})

I got error: sql: statement expects 0 inputs; got 3, so it means the placeholder didn't be parsed. Could anyone give me some idea?

I can't find out why by myself.

Please help me. Thanks.

  • 写回答

1条回答 默认 最新

  • doushao8399 2016-06-14 16:59
    关注

    You can't place a placeholder inside a string like '?'.

    It's does not work like string interpolation it's just variable binding.

    So try:

        searchKeyword := "%" + keyword + "%"
        rows, err := db.Raw(`SELECT songs.name, singers.name, albums.name 
          FROM songs, singers, albums 
          WHERE (songs.singer_id = singers.id AND songs.album_id = albums.id) 
          AND (songs.name LIKE ? OR singers.name LIKE ? OR albums.name LIKE ?)`, 
          searchKeyword, 
          searchKeyword, 
          searchKeyword).Rows()
    
    评论

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