花费很长时间执行复杂的 mySql 查询

Question

我的查询如下所示：

$result_portlist=mysql_query("
    SELECT 
        portfolio AS the_port,
        SUM(balance * course) AS the_balance,
        SUM(insurance * course) AS the_insurance
        FROM banks_all 
    WHERE CONCAT(balance, insurance)!='0'
    GROUP BY portfolio
    ",$db);

$myrow_portlist=mysql_fetch_array($result_portlist); 
if(mysql_num_rows($result_portlist)>0) { 
    do { 
        echo '<span> value1, vaule2, value3...</span>';

        $result_portlist1=mysql_query("
            SELECT 
                department AS the_department,
                SUM(balance * course) AS the_balance,
                SUM(insurance * course) AS the_insurance
            FROM banks_all 
            WHERE CONCAT(balance, insurance)!='0'
                AND portfolio='$myrow_portlist[the_port]' 
            GROUP BY department
        ",$db);

        $myrow_portlist1=mysql_fetch_array($result_portlist1); 
        if (mysql_num_rows($result_portlist1)>0) { 
            do { 
                echo '<span> value1, vaule2, value3...</span>'

                $result_portlist2=mysql_query("
                    SELECT 
                        manager_name AS the_manager,
                        SUM(balance * course) AS the_balance,
                        SUM(insurance * course) AS the_insurance
                    FROM banks_all
                    WHERE CONCAT(balance, insurance)!='0'
                        AND portfolio='$myrow_portlist[the_port]' 
                        AND department='$myrow_portlist1[the_department]'
                    GROUP BY manager_name
                ",$db);

                { 
                    do {
                        echo '<span> value1, vaule2, value3...</span>';
                    } while ($myrow_portlist2=mysql_fetch_array($result_portlist2));
                } 
            } while ($myrow_portlist1=mysql_fetch_array($result_portlist1)); 
        } 
    } while ($myrow_portlist1=mysql_fetch_array($result_portlist1)); 
} 

因此，对于具有 40,000 多行和数百种 portfolio+department+manager_name 组合的表，此查询需要数小时才能执行。我的想法是在开始时进行一个查询，将值按manager_name 分组，然后让php 分组portfolio 和department。创建此查询后，我的大脑刚刚炸毁，没有可用的内存来思考:)

请告诉我如何重新排列此查询或如何简化它以减少执行时间。

提前致谢。

编辑：这是图片，我的表（带有嵌套表）的样子：

IMAGE

Answer 1

花费大量时间的原因是您正在执行大量查询...假设您有 10 个投资组合，在 10 个部门中，您将进行 100 个查询。这个数量太疯狂了，在您的情况下减少查询数量非常简单。

我会简单地在一个查询中获取所有数据，并使用一个 3 级 group by 和一个汇总：

$result=mysql_query("
    SELECT 
        portfolio AS the_port,
        department AS the_department,
        manager_name AS the_manager,
        SUM(balance * course) AS the_balance,
        SUM(insurance * course) AS the_insurance
    FROM banks_all 
    WHERE 
        CONCAT(balance, insurance)!='0'
    GROUP BY 
        portfolio,
        department,
        manager_name 
    with ROLLUP
    ORDER BY the_port,the_department,the_manager;
",$db);
echo '<table>';
while($row = mysql_fetch_assoc($result)){
    if($row['the_port'] === null){
        //This is the big total row... Let's skip it for now shall we?
        continue;
    }
    echo '<tr>';
    if($row['the_department'] === null){
        echo '<td>Portfolio: '.$row['the_port'].'</td>';
    }else{
        if($row['the_manager'] === null){
            echo '<td>Department: '.$row['the_port'].'</td>';
        }else{
            echo '<td>Manager: '.$row['the_port'].'</td>';
        }
    }
    echo '<td>'.$row['the_balance'].'</td>';
    echo '<td>'.$row['the_insurance'].'</td>';
    echo '</tr>';
}
echo '</table>';

此查询将返回按投资组合分组、然后按部门分组、然后按经理分组的所有行。这将从最好的点（您的第三个时间）返回所有行，但使用ROLLUP，您还将按级别为其他组获得一行。这与您在同一个查询中完成 GROUP BY portfolio,department 和 GROUP BY portfolio 完全相同。

在汇总的行中，从 group by 中省略的键的值将为 NULL。所以你可以很容易地查看the_manager，当它为空时，意味着你拥有完整的部门，当the_department为空时，你拥有完整的投资组合。