mysqli if result>;0做点什么


mysqli if result > 0 do something

如何使用mysqli实现这一点?

$SQL = mysql_query("SELECT username FROM users WHERE username = '$new_username'");
$result = mysql_num_rows($SQL);
If(!$result > 0) {
echo...

我试过了:

$SQL = $mysqli->query("SELECT username FROM users WHERE username = '$utilizator");
$rezultat->num_rows($SQL);`

但是我没有得到任何结果。

您已经使用$SQL启动了查询。。继续使用它,因为对象将在该变量中:

$SQL = $mysqli->query("SELECT username FROM users WHERE username = '$utilizator'");
$num = $SQL->num_rows();
if($num){
    // run your code here
}
执行后必须调用store_result()。

php.net有一个很棒的php文档:http://www.php.net/manual/de/mysqli-stmt.num-rows.php

例如:

$query = "SELECT Name, CountryCode FROM City ORDER BY Name LIMIT 20";
if ($stmt = $mysqli->prepare($query)) {
  /* execute query */
  $stmt->execute();
  /* store result */
  $stmt->store_result();
  printf("Number of rows: %d.'n", $stmt->num_rows);
  /* close statement */
  $stmt->close();
}
$number_of_rows = $SQL->num_rows;