用MySQL计算在两个表之间重复一个String的次数

Question

Well I'm trying to get all the times that a String are repeated in two tables using a comun column and getting all the results with a While, like that:

    $result = mysql_query("SELECT * FROM hits") or die(mysql_error());

while($row = mysql_fetch_assoc( $result )) 
{
    $result=mysql_query("SELECT COUNT(app) FROM info WHERE app='$row[page]'");
while ($row = mysql_fetch_array($result, MYSQL_NUM)) 

{

$toip = $row[0] ;  
}

echo '<td bgcolor="#75D169">'; 
    echo "$toip";
    echo '</td>';

    }

But it doesn't show it very well as you can see it here: http://ikillcraft.a0001.net/counter/view.php?pass=test

The output would be:

Instalaciones de                    4       0 
Instalaciones de IkillLauncher      3       3
Instalaciones de gogogoa            3       0 
Instalaciones de MasterShell        0       0

But I don't know how to do it. :(

Answer 1

Using a single piece of SQL, something like this would do it:-

$result = mysql_query("SELECT a.page, COUNT(b.app) AS AppCount
                        FROM hits a
                        LEFT OUTER JOIN info b
                        ON a.page = b.app
                        GROUP BY a.page";

while($row = mysql_fetch_assoc( $result )) 
{
    echo '<td bgcolor="#75D169">'; 
    echo $row['AppCount'];
    echo '</td>';

}

Note I do not know your column names, and you should have all the non aggregate column names in the GROUP BY clause (ie, anything except the ones in the COUNT in this case)

Answer 2

I don't know your table structure, so I am doing guesswork here, but this should work:

SELECT hits.page, appgrouped.apphit
FROM (hits)
LEFT JOIN (SELECT COUNT(app) as apphit, app
           FROM info 
           GROUP BY app) AS appgrouped ON appgrouped.app = hits.page

This would be quite slow - depending on how big:

SELECT COUNT(app) as apphit, app
FROM info 
GROUP BY app

This is, if it is big, then the above join will be very slow, and in that case, PHP code would be a better solution (yes it would be faster).