laravel 框架结合关联查询 when()用法分析_php实例_

 $name = $request->get('name'); //活动标题 $start_time = $request->get('start_time'); //活动开始时间 $user_name = $request->get('user_name'); //发布者 $limit = (int) $request->get('limit', 15); $offset = (int) $request->get('offset', 0); $data=ActiveJieSuan::with(['user' => function ($query) {$query->select('id','name');}, 'active'=> function ($query) {$query->select('id','name','start');}]) ->when($name, function ($query) use ($name) { return $query->whereHas('active', function ($query) use ($name) { return $query->where('name', 'like', '%'.$name.'%'); }); }) ->when($user_name, function ($query) use ($user_name) { return $query->whereHas('user', function ($query) use ($user_name) { return $query->where('name', 'like', '%'.$user_name.'%'); }); }) ->when($start_time, function ($query) use ($start_time) { return $query->whereHas('active', function ($query) use ($start_time) { return $query->where('start', '>=', $start_time); }); }) ->limit($limit) ->offset($offset) ->orderBy('id', 'desc') ->paginate()->toArray(); 

 public function when($value, $callback, $default = null) { if ($value) { return $callback($this, $value) ?: $this; } elseif ($default) { return $default($this, $value) ?: $this; } return $this; }