Warning: mysql_num_rows() expects parameter 1 to be resource, boolean given in [duplicate]

Answer 1

$sql = "SELECT COUNT(*) cn FROM `apps` WHERE `MCName` = '". $username."'";
$result = mysql_query($sql);

Then get your result from that.

And yeah, I'd recommend using PDO instead of mysql_* commands

Answer 2

Your second query has an SQL syntax error:

 $sql = "SELECT * FROM `apps` WHERE `MCName` = ". $username;

The $username variable needs to be wrapped in quotes. Try updating to the following to fix:

 $sql = "SELECT * FROM `apps` WHERE `MCName` = '". $username . "'";

Answer 3

This is from php : http://php.net/manual/en/function.mysql-query.php

Use of this extension is discouraged. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:

See http://www.php.net/manual/en/mysqli.query.php for Detailed examples

Proper way to do it ??

$mysqli = new mysqli("localhost", "user", "password", "db");
$sql = "SELECT * FROM `apps` WHERE `MCName` = '%s' ";

if ($mysqli->connect_errno) {
    printf("Connect failed: %s\n", $mysqli->connect_error);
    exit();
}

$result = $mysqli->query(sprintf($sql, $mysqli->real_escape_string($username)));
$rows = $result->num_rows;