php 'no database selected' but it is connected to the database

Question

I have checked other questions with the same title but can't fix this. I have connected to the database though because the login works and I can display the user's username. Here is the relevent code, the second part is what's causing the error, thanks:

<?php require 'connection.php' ?>
<?php
session_start();
?>


<content>
                <?php
                //Select all from the categories table and order by the  category title in ascending order (ASC)
                $sql = "SELECT * FROM categories ORDER BY category_title ASC";

                //$res = the result of the above query or die if error
                $res = mysql_query($sql) or die (mysql_error());

                if (mysql_num_rows($res) > 0) {

                } else {
                    "<p>No categories availible</p>";
                }


                ?>

                </content>

first , mysql_* function are deprecated use mysqli or PDO ! Second , use require_once instead of require Finally, show us connection.php — Fky, Sep 11 '15 at 15:35
someone create an answer so we can reward you, before the Big Dogs close this question — Drew, Sep 11 '15 at 15:37
If you can, you should [stop using `mysql_*` functions](http://stackoverflow.com/questions/12859942/why-shouldnt-i-use-mysql-functions-in-php). They are no longer maintained and are [officially deprecated](https://wiki.php.net/rfc/mysql_deprecation). Learn about [prepared](http://en.wikipedia.org/wiki/Prepared_statement) [statements](http://php.net/manual/en/pdo.prepared-statements.php) instead, and consider using PDO, [it's really not hard](http://jayblanchard.net/demystifying_php_pdo.html). — Jay Blanchard, Sep 11 '15 at 15:37
`Connected !== database selected` You can select the database programmatically or you can name it in your query: `SELECT * FROM database_name.table_name` etc — Jay Blanchard, Sep 11 '15 at 15:38
I have used mysqli_query($sql) instead, but now says that this function requires 2 parameters. Any idea what the second parameter should be (sorry still learning). Thanks — gogo123, Sep 11 '15 at 15:43
check documentation http://php.net/manual/en/mysqli.query.php — Fky, Sep 11 '15 at 15:44
Assuming you're on Windows. bestoffred.txt would fail to load on Linux ;-) @Drew — Funk Forty Niner, Sep 11 '15 at 15:59

Drew · Answer 1 · 2015-09-11T15:50:29.547

Here is an example, for the visual of it.

<?php
    $dbname = 'so_gibberish';
    $dbuser = 'GuySmiley';
    $dbpass = 'MyPassword';
    $dbhost = 'localhost';
    $link = mysql_connect($dbhost, $dbuser, $dbpass) or die("Unable to Connect to '$dbhost'");
    mysql_select_db($dbname) or die("Could not open the db '$dbname'");

    $test_query = "SHOW TABLES FROM $dbname";
    $result = mysql_query($test_query);
    ...
    ...
    mysql_close($link);

However, go with PDO

It is less sickly, full of robustness, and safer to say the least for binding:

Again, just a visual.

<?php
    $theNum=102;    // get from user, this is hard-coded
    try {
        $dbh = new PDO('mysql:host=localhost;dbname=so_gibberish;charset=utf8', 'GuySmiley', 'MyPassword');
        $dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

        $stmt = $dbh->prepare('SELECT id,smin,smax from ranges7 
            WHERE smin <= :theNum AND smax >= :theNum');
        $stmt->bindParam(':theNum', $theNum, PDO::PARAM_INT);
        $stmt->execute();
        while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
            // one row we hope
            $data = "id: ".$row['id'] . ", smin: " . $row['smin'] . ", smax: " . $row['smax'] . "\n";
            print $data;
        }
        $stmt = null;
        // PDO closes connection at end of script

    } catch (PDOException $e) {
        echo 'PDO Exception: ' . $e->getMessage();
        exit();
    }
?>

Thank you all, I used the mysqli_query() with DBconnect as the first parametre and it worked. — gogo123, Sep 11 '15 at 15:50
I think Jay and I should invite him over for our autumn BBQ @Fred-ii- — Drew, Sep 11 '15 at 16:23
dang @Fred-ii-, my Zeus Prometheus Pandora history lesson vanished for *most* of us — Drew, Sep 11 '15 at 18:49
@Drew Get that 10k man, so you can still see those *after the fact* deleted questions/answers. — Funk Forty Niner, Sep 11 '15 at 18:50

php 'no database selected' but it is connected to the database

1 Answers1

However, go with PDO