在非对象中调用成员函数fetch_assoc（）。错误的PHP代码？

Question

$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}


$sql="SELECT Nr FROM AlleTransaktionen1";
$my_money = 0;
if ($conn->multi_query($sql) === TRUE) {
    $result = $conn->query($sql);
    while($row = $result->fetch_assoc()) {
        echo"$row[Nr]";
    }
    echo "$my_money";
} else {
    echo"Fehler: " . $sql . "<br>" . $conn->error;
}
$conn->close();

I get the error:

Call to a member function fetch_assoc() on a non-object in...

Answer 1

<?php
$conn = new mysqli($servername, $username, $password, $dbname);

/* check connection */
if ($conn->connect_errno) {
  printf("Connect failed: %s
", $conn->connect_error);
  exit();
}

$sql = "SELECT Nr FROM AlleTransaktionen1";

$my_money = 0;

if ($result = $conn->query($sql)) {

  /* fetch associative array */
  while ($row = $result->fetch_assoc()) {
    printf ($row["Nr"]);
}

/* free result set */
  $result->free();
}

/* close connection */
  $mysqli->close();
?>