Wordpress中的SQL查询问题

Question

I'm using the exec php plugin to have php code inside my pages. I've imported a table into the wordpress db and copied my original query over into a page but I can't seem to get it working.

I can't tell what's wrong because there is no sql error thrown onto the page, all it does is stop executing once it reached the query.

$query = "SELECT * FROM 'classSchedule' ORDER BY 'age' ASC";
$result = mysql_query ($query, $link) or die (mysql_error());

$num_rows = mysql_num_rows ($result);
if ($num_rows != "0")
{
    echo "Select a Class";
    while ($row = mysql_fetch_array($result))
    {
        $day = $row['day'];
        $time = $row['time'];
        $class = $row['class'];
        $age = $row['age'];
        $level = $row['level'];

        echo "(Age: $age) $day $time $class Level: $level";
    }
}

I've also tried testing with example code in the wpdb codex but even that isn't working.

$mylink = $wpdb->get_row("SELECT * FROM $wpdb->wp_links WHERE link_id = 2");
echo $mylink->link_id;

Someone please help! I'm using wordpress 3.1.

EDIT Okay I've solved it by adding global $wpdb to the top of the code.

Answer 1

Try removing the ticks around classSchedule and age . Those look like normal apostrophes ('). If you want to encase table and column names in MySQL (which is optional), use backticks (`).