Question

function countBrand($brand_id, $brand_name) {
    $sql = "SELECT brand FROM coupons WHERE expire >= CURRENT_DATE AND brand='".$brand_id."'";
    $result = mysql_query($sql);
    $row = mysql_fetch_array($result);
    echo '<li>'.$brand_name.'</li>';
}

function brandCount() {
    $sql = "SELECT DISTINCT brand,brand_id,brand_name FROM coupons,coupons_brand WHERE brand=brand_id AND expire >= CURRENT_DATE ORDER BY brand_name";
    $result = mysql_query($sql);
    $row = mysql_fetch_array($result);
    $num = mysql_num_rows($result);

    echo '<h3>'.$num.' Brands</h3>';

    echo '<ul>';

    $i = 0;
    while ($i < $num) {
        $brand_id = mysql_result($result, $i, "brand_id");
        $brand_name = mysql_result($result, $i, "brand_name");
        countBrand($brand_id, $brand_name);
        $i++;
    }

    echo '</ul>';
}

It works perfectly and gives me the results I am looking for. I am not as strong with sql statements as I would like to be. Is there a way I could do this that would be more efficient, it seems very slow.

Basically, it counts how many brands have coupons, then coupons how many coupons each brand has..

I also, on the same page, do this for categories. There are a few thousand categories and maybe 20,000 coupons.

Answer 1

there are a few php optimisations you could do, but they probably wont save you much time, compared to adding an index to mysql on the correct columns

i have commented some php optimisations below, maybe of interest to you anyway

given the simple nature of the functions, it is not necessary to have 2 functions, and that would save the timecost of calling countBrand(), (although it is a pretty minimal time saving)

   function countBrand($brand_id, $brand_name) {
        $sql = "SELECT brand FROM coupons WHERE expire >= CURRENT_DATE AND brand='".$brand_id."'";
        $result = mysql_query($sql) || die (mysql_error()); // always check for errors

        list($brand) = mysql_fetch_row($result);

// fetch row, returns a more concise array then mysql_fetch_array
//        $row = mysql_fetch_array($result);

        // use commas rather then . when concatenating echo statements
        // dots force concatenation before output
        echo '<li>',$brand,'</li>'; 

    }

    function brandCount() {
        $sql = "SELECT DISTINCT brand,brand_id,brand_name FROM coupons,coupons_brand WHERE brand=brand_id AND expire >= CURRENT_DATE ORDER BY brand_name";
        $result = mysql_query($sql) || die(mysql_error()); // always check for errors

    //    $row = mysql_fetch_array($result); // not sure why this is needed
        $num = mysql_num_rows($result); 

        // use commas rather then . when concatenating echo statements
        // dots force concatenation before output
        echo '<h3>',$num,' Brands</h3>';

        echo '<ul>';

      // fetch all cols at once, rather then using lots of separate calls to mysql_result
      // use mysql_fetch_row as it returns just the ordered values (vs mysql_fetch_assoc, and mysql_fetch_array)
      // 
       while(list($brand, $brand_id, $brand_name) == mysql_fetch_row($result)) {
            countBrand($brand_id, $brand_name);
       }

      // replaced with while loop above
      //  $i = 0;
      //  while ($i < $num) {
      //      $brand_id = mysql_result($result, $i, "brand_id");
      //      $brand_name = mysql_result($result, $i, "brand_name");
     //       countBrand($brand_id, $brand_name);
      //      $i++;
        }

        echo '</ul>';
    }

those enhancements will only give you a minor speed increase
the biggest speed increase you will get is if you call the database less.

currently you select each brand, and then go back and count each brand individually
without knowing the structure of you tables this sql is difficult for me to write, so it is a guess, but it should point you in the right direction

SELECT brand, brand_id, brand_name, COUNT(*) as brandcount
FROM coupons
JOIN coupons_brand ON brand=brand_id 
WHERE expire >= CURRENT_DATE 
GROUP BY brand, brand_id, brand_name
ORDER BY brand_name