Re: Return values from mysql_query

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David Killen wrote:

> I'm just beginning with PHP and came across something which is
> frustrating me no end. I have a really simple script which given a
> username will query the database and if it doesn't find a match will
> then insert into the database. The problem I find is that even when
> there is no data in the database to match the return from mysql_query
> evaluates to true even though all the documentation and tutorials that I
> have read say that mysql_query should return false when using a SELECT
> query if there is no match. Am I missing something really simple here or
> is there another explaination as to why this might be the case? The
> following code snippet exhibits this behaviour. I am running the
> following: Apache 2.0.54, PHP 5.0.5-2, MySQL 4.1.12.
> 
> <?php
>     $username = "david";
>     $conn = mysql_connect('localhost','user','pass');
>     mysql_select_db('test',$conn);
>     $sql = "SELECT * FROM users WHERE username='$username'";
>     echo $sql."<br/>";
>     $result = mysql_query($sql,$conn);
>     echo $result."<br/.>";
>     if (!$result)
>         echo "No Match!<br/>";
>     else
>     {
>         $row = mysql_fetch_array($result);
>         while ($row)
>        {
>             echo $row['username'].' -- '.$row['email'].'<br/>';
>             $row = mysql_fetch_array($result);
>         }
>     }
>     mysql_close();
> ?>
> 
> Cheers,
> 
> David

The function mysql_query just returns false when it get an error in that
query. When do you wanto to know if is there some match, you ought to use
mysql_num_rows($result). It'll return the number of lines was found by your
query.

Hope helping.

-- 
---------------------------------------------------
João Cândido de Souza Neto
Web Developer

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