在Golang中显示来自数据库的结果

Question

I'm reading a MySQL query input from a form:

<h1>MySQL Page</h1>
<small>Perform queries and edit the database from here</small>
<form method="get" action="">
  <label for="sqlQuery">MySQL Query:</label>
  <input type="text" id="sqlQuery" name="sqlQuery">
  <button type="submit">Perform Query</button>
</form>

After that I want to display the results on the same page using GoLang, however it keeps telling me that:

# command-line-arguments
./sql.go:128: cannot convert results (type sql.Result) to type string

Please keep in mind, this is the first golang app I've ever written so I apologize if this is a simple issue, here is the golang code:

func sqlQueryHandler(response http.ResponseWriter, request *http.Request){
  userName := getUserName(request)
  db, err := sql.Open("mysql", userName)
  fmt.Fprintf(response, sqlPage)
  sqlCommand := request.FormValue("sqlQuery")
  //fmt.Fprintf(response, sqlCommand)
  if err != nil {
    fmt.Fprintf(response, "

An error occured during your MySQL command: %s", err)
    panic(err)
  } else {
    data, err := db.Exec(sqlCommand)
    if err != nil {
      http.Redirect(response, request, "/error", 302)
    } else {
      // display the output of the sql query here
    }
  }
}

Answer 1

Here an example based on your code:

func sqlQueryHandler(response http.ResponseWriter, request *http.Request) {
    var (
        userName   = getUserName(request)
        sqlCommand = request.FormValue("sqlQuery")
    )

    db, err := sql.Open("mysql", userName)
    if err != nil {
        fmt.Fprintf(response, "

An error occured during your MySQL command: %s", err)
        // if you panic you stop here anyway. no else needed
        panic(err)
    }
    rows, err := db.Query(sqlCommand)
    if err != nil {
        http.Redirect(response, request, "/error", 302)
        // return, so no else is needed
        return
    }

    if err != nil {
        panic(err)
    }
    defer rows.Close()
    for rows.Next() {
        var (
            name string
            age  int
        )
        if err := rows.Scan(&name, &age); err != nil {
            panic(err)
        }
        fmt.Printf("%s is %d
", name, age)
    }
    if err := rows.Err(); err != nil {
        panic(err)
    }
}

There are several problems however with this approach:

• You are passing the sql from outside the server. Anyone accessing this can read all the data from your server.
• One of Go's strengths is being a typed language. Here you are building a general sql query function which contradicts the typed language paradigm. You can write general function dealing with differently structured data (like json.Unmarshal()) -- but especially early in programming go you shouldn't.