laravel緩慢查詢問題

Question

我想優化我的查詢，我正在使用Laravel執行。我爲我的項目使用MySQL，並且我有一個名爲locations的表。它有超過200萬條記錄。 當我執行下面的代碼時，它太慢了。如何優化我的查詢以提高速度？

foreach ($employees as $employee){ 
    $percentage = 0; 
    if ($employee->position->zones->count() > 0) { 
     if($employee->position->zones->first()->workingzones->count() > 0) { 
      $workingZone = $employee->position->zones->first()->workingzones->last(); 
      $tagCode = $employee->rfids->first()->rfid_id; 
      $zoneTime = DB::table('location') 
       ->select(DB::raw('count(*) as count')) 
       ->where('tagCode', $tagCode) 
       ->where('xLocation', '>', $workingZone->x1) 
       ->where('xLocation', '<', $workingZone->x3) 
       ->where('yLocation', '>', $workingZone->y3) 
       ->where('yLocation', '<', $workingZone->y1) 
       ->where('locationDate', '>=',''.$currentDate.' 00:00:01') 
       ->where('locationDate', '<=', $currentDate. ' 23:59:59') 
       ->get(); 


      $totalWorkedTime = DB::table('location') 
       ->select(DB::raw('count(*) as count')) 
       ->where('tagCode', $tagCode) 
       ->where('locationDate', '>=',''.$currentDate.' 00:00:01') 
       ->where('locationDate', '<=', $currentDate. ' 23:59:59')->get(); 


       if ($zoneTime->first()->count == 0 || $totalWorkedTime->first()->count == 0) { 
        $percentage = 0; 
       }else { 
        $percentage = (int)ceil(($zoneTime->first()->count /12)* 100/($totalWorkedTime->first()->count/12)); 
       } 
      } 
     } 

     $employee->percentage = $percentage; 
    } 

Answer 1

以下列添加索引要提高你的表現：

• xLocation
• yLocation
• locationDate

如何用MySQL查詢添加索引： https://dev.mysql.com/doc/refman/5.7/en/create-index.html

，或者如果您使用Laravel的遷移：https://laravel.com/docs/5.4/migrations#indexes

編輯：

另外：與其做兩個選擇查詢的COUNT(*)，使用COUNT(`id`)，所以你不要指望所有列，但只有id列

Answer 2

您執行完整->get()兩次，只使用->first()結果。當你只需要1時，只需使用->first()而不是->get()。 （ - 分組eagerload查詢總）

---

您也可以同時獲取員工，並節省2次額外的查詢每圈eagerload的位置和區域，像這樣：

$employees = Employee::where(/*where foo here*/) 
    ->with('position.zones') 
    ->get(); 

---

而且消耗更少的內存，大塊它。

Employee::where(/*where foo here*/) 
    ->with('position.zones') 
    ->chunk(200, function ($employees) { 
     foreach ($employees as $employee) { 
      // current code here with ->first() instead of ->get() 
     } 
    });