title: unsupported Scan, storing driver.Value type
body: <p>I want to select fild in database and return 3 vriables with golang, 
  this is my actual code :</p>
  
  <pre><code>func db_tabela_select(cliente string) (id string, cod1 string, cod2 string, cod3 string) {
  
      db, err := sql.Open("mysql", mysql_login)
      if err != nil {
          log.Fatal(err)
      }
      defer db.Close()
  
      err = db.Ping()
      if err != nil {
          log.Fatal(err)
      }
  
  
      var Saldo, grup1, grup2, grup3, timestamp, user_agent string
  
      err = db.QueryRow(fmt.Sprintf("select * from db_tabela WHERE `cliente`='%s' LIMIT 1;", string(cliente) )).Scan(
          &amp;id, &amp;cliente, &amp;Saldo, &amp;cod1, &amp;cod2, &amp;cod3, &amp;grup1, &amp;grup2, &amp;grup3, &amp;user_agent, &amp;timestamp)
      if err != nil {
          fmt.Println(err)
      } else {
          log.Printf("cod results : ", cod1, cod2, cod3)
      }
  
  
      return id, cod1, cod2, cod3
  }
  </code></pre>
  
  <p>return me this error, and i don't understend where is my mistake:</p>
  
  <pre><code>sql: Scan error on column index 2: unsupported Scan, storing driver.Value type &lt;
  nil&gt; into type *string
  </code></pre>