How to get number of returned rows from a database

After I perform a database query, and some rows are echoed, it seems that I can't get the number of rows which are shown, after the query.开发者_如何学Python Tried to use mysql_num_rows() but my $result is like this:

$result = $conn->query($sql) or die();

so I think that the problem is that I've used the built-in MySQLi() class, and for some reason mysql_num_rows() is not working in accordance with this $result. How can I get it to work with the current $result I'm using, or is there any other way to return the number of rows using the MySQLi() class to create the $result??

mysql and mysqli are NOT interchangeable. They're two completely different modules, maintain their own separate connections, and are results/handles from one are NOT useable in the other. They may both use the same underlying mysql libraries and talk to the same database, but they're utterly independent of each other.

If you're using MySQLi, then stick with MySQLi functions, which for your problem would be to use http://php.net/manual/en/mysqli-stmt.num-rows.php

Note1: If you only need the number of rows in your table, it is better to do the folowing:

$result = $conn->query("SELECT COUNT(*) FROM `table`");
$row = $result->fetch_row();
echo '#: ', $row[0];

Note 2: Don't mix up mysqli_field_count and mysqli_stmt_num_rows. For example :

id firstname
1  foo
2  bar
3  baz

• field_count is 2
• num_rows is 3