Question

The code below works great. I have a MySQL database that contains book titles classified in different categories. In the code below, the variable “site” represents a book title. Each category is represented by a different table in the MySQL database.

The code below ranks the top 25 book titles (site) by total votes across all categories (MySQL tables). I am trying to exclude blank book titles (i. e. when site = ”). How can I do this?

I have tried inserting WHERE site != '' in a few places but I get an error message. So I guess I’m asking, where can I insert WHERE site != ''?

Thanks in advance,

John

<?

mysql_connect("mysqlv10", "username", "password") or die(mysql_error());
mysql_select_db("database") or die(mysql_error());

$result = mysql_query("SHOW TABLES");
$tables = array();
while ($row = mysql_fetch_assoc($result)) {
    $tables[] = '`'.$row["Tables_in_bookfeather"].'`';

}

$subQuery = "SELECT site, votes_up FROM ".implode(" UNION ALL SELECT site, votes_up FROM ",$tables);
// Create one query that gets the data you need
$sqlStr = "SELECT site, sum(votes_up) sumVotesUp
            FROM (
            ".$subQuery." ) subQuery
           GROUP BY site ORDER BY sum(votes_up) DESC LIMIT 25";
$result = mysql_query($sqlStr);

$arr = array(); 
echo "<table class=\"samples2\">";
while ($row = mysql_fetch_assoc($result)) { 
    echo '<tr>';
    echo '<td class="sitename2"><a href="booklookup3.php?entry='.urlencode($row["site"]).'&searching=yes&search=search">'.$row["site"].'</a></td>';
    echo '<td>'.$row["sumVotesUp"].'</td>';
    echo '</tr>';
} 

echo "</table>";



?>

Answer 1

It’s probably safest to put it in the subquery:

$subQueryParts = array();
foreach($tables as $table)
    $subQueryParts[] = "SELECT site, votes_up FROM $table WHERE LENGTH(site)";
$subQuery = implode(" UNION ALL ", $subQueryParts);

If possible, you should follow Bill Karwin’s advice and store all your books in one table. Dynamic table names are very hard to search and manage, and they do not optimize well.