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I have a simple PHP login function. Within this function, I am checking to see if the user exist by making a MySQL query that is selecting username from a table and counting the number of rows that is returned. I am having trouble with the query returning null when I know for a fact that the table contains the username.

Here is my code.

function login($user_name, $password) {
    $db1 = new DB_CONNECT();        
    $db1->connect();

    $query = "SELECT user_name FROM users WHERE user_name = '$user_name'";
    $result = $db1->makeAQuery($query);

    if (mysql_num_rows($result) == 1) {
        //check the password
    }
    else {
        //no user exist 
    }
}


I know that the username and password that are coming in are OK and I trim for any white spaces before I sent them to the function. I know that the database connection is working because it works on the rest of my PHP code. The only error that I am getting is one that mentions that the mysql_num_rows "expects parameter 1 to be resource, null given"

Database class

class DB_CONNECT {
    function connect() {
        // import database connection variables
        require_once __DIR__ . '/db_config.php';
        $con = mysql_connect(DB_SERVER, DB_USER, DB_PASSWORD) or die(mysql_error());

        // Selecing database
        mysql_select_db(DB_DATABASE, $con) or die(mysql_error());
    }
    function makeAQuery($query) {
        $result = mysql_query($query) or die(mysql_error());        
    } 
    function close() {
       // closing db connection
    mysql_close();
    }
}
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2  
what is the code for the DB_CONNECT class? – Kris Mar 14 at 13:39
2  
and p.s. xkcd.com/327 – Kris Mar 14 at 13:41
@Kris Nice one :) – Bigood Mar 14 at 13:42
1  
as above, but also STOP using mysql_* built in functions. php.net/manual/en/function.mysql-num-rows.php – djjjuk Mar 14 at 13:43
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closed as not constructive by echo_me, NikiC, akond, Benjamin Gruenbaum, p.s.w.g Mar 14 at 18:54

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2 Answers

up vote 0 down vote accepted

This should work:

"SELECT user_name FROM users WHERE user_name = '".$user_name."'";

Also

change this:

function makeAQuery($query) {
    $result = mysql_query($query) or die(mysql_error());        
}

to

function makeAQuery($query) {
    $result = mysql_query($query) or die(mysql_error());      
    return   $result;
}
share|improve this answer
The Return statement did it. After all that, I forgot a simple statement. – Joshua Peters Mar 14 at 14:12
glad to help ;) – rinchik Mar 14 at 14:13
up vote -1 down vote

Maybe try removing the spaces between the = in the query. 

"SELECT user_name FROM users WHERE user_name='$user_name'"

Your script may be returning null because the query could not run.

share|improve this answer
i can make it WHERE user_name = many_space_here '$user_name' and it will work – echo_me Mar 14 at 13:50
Ah sorry, I forgot MySQL does not care for whitespace. – George Mickleburgh Mar 14 at 13:54
With or without spaces, the samething – Joshua Peters Mar 14 at 13:57

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