SQL插入查询返回false

Question

为什么我的查询失败？列在那里。是否存在语法问题或者我应该在其他地方查找？

 if (isset($_POST['username']) && isset($_POST['password'])) {
    $username = $_POST['username'];
    $password = $_POST['password'];
    $result = mysqli_query
    (
     $conn, "INSERT INTO users (username, password) VALUES ('$username','$password')"
    );
    if($result === false) {
        echo 'query failed for some reason';
    }
    if ($end = mysqli_fetch_array($result) > 0) {
        echo "succ";
        mysql_close($conn);
    } else {
        echo 'fail';
        die('Could not insert into database:' . mysql_error());
    };
}

Answer 1

如果从mysql_query插入，则在代码中 然后它不会返回行，所以你不需要mysql_fetch_assoc（）

if (isset($_POST['username']) && isset($_POST['password'])) {
    $username = $_POST['username'];
    $password = $_POST['password'];
    $result = mysqli_query
    (
     $conn, "INSERT INTO users (username, password) VALUES ('$username','$password')"
    );
    if($result === false) {

        echo 'query failed for some reason';
        die('Could not insert into database:' . mysqli_error($conn));
    } else {
        echo "succ";
        mysqli_close($conn);
    }
}