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>';
}

它完美运作，并给我我想要的结果。我不像我想的那样强大的sql语句。有没有办法可以做到更有效率，看起来很慢。

基本上，它计算有多少品牌有优惠券，然后优惠券每个品牌有多少优惠券..

我也在同一页面上为类别执行此操作。有几千种类别，可能有20,000张优惠券。

Answer 1

你可以做一些PHP优化，但与在正确的列上添加索引到mysql相比，它们可能不会节省你很多时间

我评论了下面的一些php优化，无论如何你可能感兴趣

考虑到函数的简单特性，没有必要有2个函数，这样可以节省调用countBrand（）的时间成本，（尽管节省的时间非常少）

   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>';
    }

这些增强功能只能为您带来轻微的速度提升如果你少打电话给数据库，你将获得的最大速度提升。

目前您选择每个品牌，然后返回并单独计算每个品牌在不知道你的表结构的情况下，这个sql对我来说很难写，所以这是猜测，但它应该指向正确的方向

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

Answer 2

mysql_fetch_array（$结果，的 MYSQL_ASSOC ）;

SELECT SQL_CACHE brand FROM

Profiling query

有没有更有效的方法来做到这一点

2 个答案: