mysqli_num_rows返回false而不是true [关闭]

Question

I have difficulties getting rows from a table in a database because mysqli_num_rows always returns false. This is an extract of my code:

$query = "SELECT * FROM table1 WHERE user = '$user'";
if (mysqli_num_rows(mysqli_query($conn, $query)))
{
$row = mysqli_fetch_row($results);
echo $row[1]
}

I did not get the result of the echo $row[1]. I then substituted the if statement with another:

    if (!mysqli_num_rows(mysqli_query($conn, $query)))
    echo 'no rows!'

and got 'no rows!' on the browser.

I have successfully connected to the database and other queries work just fine. Please, I would like to understand why mysqli_num_rows will return false even though I have rows in the table which match the query.

Answer 1

It should be

$query = "SELECT * FROM table1 WHERE user = '$user'";
if (mysql_num_rows(mysql_query($query)) > 0){
$row = mysql_fetch_row($results);
  echo $row[1];
}else{
  echo 'user does not exist'; 
}