PHP查询加载太慢。如何提高速度？

Question

有没有人知道更有效的方法来写下面的代码。我现在的加载时间超过了一分钟。这是我在一个更长的代码集之后想出来的。

$max = $i + 25;
while ($i < $max)
  {
    $memberno = $memberid;
    if($pulledid!=$memberid)
      {
        $pulledid = mysql_result($result99,$i,"id_member");
        $sql_statement = "Select vinyl_fortrade.ImageID,vinyl_fortrade.MemberID from vinyl_fortrade where exists (Select ImageID from vinyl_wanted WHERE MemberID = $memberno AND vinyl_wanted.ImageID = vinyl_fortrade.ImageID) AND vinyl_fortrade.MemberID=$pulledid";
        $result=mysql_query($sql_statement)or die(mysql_error());    
        $num=mysql_numrows($result);
        if($num>0)
          {
            $sql_statement2 = "Select vinyl_wanted.ImageID, vinyl_wanted.MemberID from vinyl_wanted where exists (Select ImageID from vinyl_fortrade WHERE MemberID = $memberno AND vinyl_wanted.ImageID = vinyl_fortrade.ImageID) AND vinyl_wanted.MemberID=$pulledid";
            $result2=mysql_query($sql_statement2)or die(mysql_error());                
            $num2=mysql_numrows($result2);
            $membername = mysql_result($result99,$i,"smf_members.member_name");
            $userid2 = mysql_result($result99,$i,"smf_members.id_member");
            if ($num2 > 0)
              {
                $lastlogged = mysql_result($result99,$i,"smf_members.last_login");
                echo '<td><a href="http://vinylmationconnection.com/forum/index.php?action=pm;sa=send;    u='.$userid.'"style="color: #FFF">'.$membername.'</a><br>Last Logged In:<br>';
                echo date('Y-m-d', $lastlogged);
                echo ':</td>';
                echo '<td>';
                $n = 0;
                $m = 0;
                while ($n < $num)
                  {
                    $title=mysql_result($result,$n,"vinyl_fortrade.ImageID");
                    $sql_statementj = "Select * from vinyl_figures WHERE ImageID = '$title'";
                    $resultj=mysql_query($sql_statementj)or die(mysql_error());  
                    $seriess=mysql_result($resultj,0,"vinyl_figures.Series");
                    echo '<img  src="http://vinylmationconnection.com/images/p'.$seriess.'/'.$title.'.jpg">';
                    $n++;
                    if($n%4=="0")
                      echo "<br>";
                  }
                echo '</td><td>';
                while ($m < $num2)
                  {
                    $title=mysql_result($result2,$m,"vinyl_wanted.ImageID");
                    $sql_statementj = "Select Series from vinyl_figures WHERE ImageID = '$title'";
                    $resultj=mysql_query($sql_statementj)or die(mysql_error());  
                    $seriess=mysql_result($resultj,0,"vinyl_figures.Series");
                    echo '<img src="http://vinylmationconnection.com/images/p'.$seriess.'/'.$title.'.jpg">';
                    $m++;
                    if($m%4=="0")
                      echo "<br>";
                  }                              
                echo '</td> </tr>';
              }
          }
      }
    $i++;
  }

请让我知道如果这个代码是不言自明的。

Answer 1

$sql_statementj = "Select * from vinyl_figures WHERE ImageID = '$title'";
$sql_statementj = "Select Series from vinyl_figures WHERE ImageID = '$title'";

在这两条语句中，如果我的代码正确的话，您似乎对同一文件发出了一个mysql请求。在循环之外发出这些请求，这应该会做一些工作。

Answer 2

编写一个存储过程(也许一个简单的查询/视图就足够了)来完成所有这些查询工作，并监视数据库索引。

Answer 3

WHERE EXISTS子句几乎可以肯定是罪魁祸首，应该对其进行重构。慢速查询的一般指南...

1. 使用EXPLAIN SELECT查看查询的实际操作
2. 在WHERE、JOIN、ORDER、GROUP
3. Avoid *中使用的所有列上添加索引，而只选择您需要的列
4. 将限制添加到不需要完整表扫描的所有查询中。