请教关于php中execl导出，循环时间的问题

做php导出，需要循环输出数据到execl中，一开始写了一个，觉得时间有点长，就缩短了下，发现时间还变多了，求教这是为什么啊？谢谢了先。

原先的代码片段：

//归总每个一级分类下的二级分类
foreach($first_cate_array as $fkey => $fvalue){
    foreach($cate as $ck=>$cv){                             
        if($cv['parentid'] == $fvalue['id']){
            $first_cate_array[$fkey]['second_cate'][] = $cv;
        }
    }

    //获得每个一级分类下二级分类的数目
    $second_count = count($first_cate_array[$fkey]['second_cate']); 
    $first_cate_array[$fkey]['second_count'] = $second_count == 0 ? 1 : $second_count;  
}

/*************************************************************************/
foreach($first_cate_array as $fk => $fv){
    //一级目录起始行数
    if($fk == 0){
        $stapos = $num;
        $en_stapos = $stapos+$cate_count;
    }else{
        $stapos = $stapos+$first_cate_array[$fk-1]['second_count'];
        $en_stapos = $stapos+$cate_count;
    }

    foreach($fv['second_cate'] as $sck => $scv){
        //二级目录起始行数
        $stapos1 = $stapos+$sck;
        $en_stapos1 = $en_stapos+$sck;
        foreach($scv['pro'] as $spk => $spv){
            $str1 = 70+$spk*3;
            $str1 = chr($str1);
            $str2 = 71+$spk*3;
            $str2 = chr($str2);
            $str3 = 72+$spk*3;
            $str3 = chr($str3);
            //中文
            $collect = $spv['name'].'（'.$spv['description'].'）';
            $objActSheet->setCellValue($str1.$stapos1, $collect);
            $objActSheet->setCellValue($str2.$stapos1, $spv['name']);
            $objActSheet->setCellValue($str3.$stapos1, $spv['description']);
            //英文
            $en_collect = $spv['en_name'].'('.$spv['en_description'].')';
            $objActSheet->setCellValue($str1.$en_stapos1, $en_collect);
            $objActSheet->setCellValue($str2.$en_stapos1, $spv['en_name']);
            $objActSheet->setCellValue($str3.$en_stapos1, $spv['en_description']);
        }
        //中文
        $objActSheet->setCellValue('E'.$stapos1, $scv['category']);
        //英文
        $objActSheet->setCellValue('E'.$en_stapos1, $scv['en_category']);
    }
    //中文
    $objActSheet->setCellValue('D'.$stapos, $fv['category']);
    $stopos = $stapos + $fv['second_count'] - 1;
    $mergecellstr = 'D'.$stapos.':D'.$stopos;
    $objActSheet->mergeCells($mergecellstr);
    //英文
    $objActSheet->setCellValue('D'.$en_stapos, $fv['en_category']);
    $en_stopos = $en_stapos + $fv['second_count'] - 1;
    $en_mergecellstr = 'D'.$en_stapos.':D'.$en_stopos;
    $objActSheet->mergeCells($en_mergecellstr);
}

修改以后的片段：

$second_count = 0;
//归总每个一级分类下的二级分类
foreach($first_cate_array as $fkey => $fvalue){
    //一级目录起始行数
    $stapos = $num+$second_count;
    $en_stapos = $stapos+$cate_count;
    $second_stapos = 0;
    foreach($cate as $ck=>$cv){
        if($cv['parentid'] == $fvalue['id']){
            //二级目录起始行数
            $stapos1 = $stapos+$second_stapos;
            $en_stapos1 = $en_stapos+$second_stapos;                                    
            foreach($cv['pro'] as $spk => $spv){
                $str1 = 70+$spk*3;
                $str1 = chr($str1);
                $str2 = 71+$spk*3;
                $str2 = chr($str2);
                $str3 = 72+$spk*3;
                $str3 = chr($str3);
                //中文
                $collect = $spv['name'].'（'.$spv['description'].'）';
                $objActSheet->setCellValue($str1.$stapos1, $collect);
                $objActSheet->setCellValue($str2.$stapos1, $spv['name']);
                $objActSheet->setCellValue($str3.$stapos1, $spv['description']);
                //英文
                $en_collect = $spv['en_name'].'('.$spv['en_description'].')';
                $objActSheet->setCellValue($str1.$en_stapos1, $en_collect);
                $objActSheet->setCellValue($str2.$en_stapos1, $spv['en_name']);
                $objActSheet->setCellValue($str3.$en_stapos1, $spv['en_description']);
            }
            //中文
            $objActSheet->setCellValue('E'.$stapos1, $cv['category']);
            //英文
            $objActSheet->setCellValue('E'.$en_stapos1, $cv['en_category']);
            $second_stapos ++ ;
            $second_count ++ ;
        }
    }                           
    //中文
    $objActSheet->setCellValue('D'.$stapos, $fvalue['category']);
    $stopos = $num + $second_count - 1;
    $mergecellstr = 'D'.$stapos.':D'.$stopos;
    $objActSheet->mergeCells($mergecellstr);
    //英文
    $objActSheet->setCellValue('D'.$en_stapos, $fvalue['en_category']);
    $en_stopos = $num + $cate_count + $second_count - 1;
    $en_mergecellstr = 'D'.$en_stapos.':D'.$en_stopos;
    $objActSheet->mergeCells($en_mergecellstr);
}

我觉得原先的代码多一个上面的循环，时间应该多一点。查询1700条数据耗时84s。