ThinkPHP5.0 模型聚合操作

1、count 統計數量，參數是要統計的字段名（可選填）

//靜態調用
User::count();
User::where('status','>',0)->count();

//動態調用
$user = new User;
$user->count();
$user->where('status','>',0)->count();

2、max 獲取最大值，參數是要統計的字段名（必填）

//靜態調用
User::max('score');
User::where('status','>',0)->max('score');

//動態調用
$user = new User;
$user->max('score');
$user->where('status','>',0)->max('score');

3、min 獲取最小值，參數是要統計的字段名（必填）

//靜態調用
User::min('score');
User::where('status','>',0)->min('score');

//動態調用
$user = new User;
$user->min('score');
$user->where('status','>',0)->min('score');

4、avg 獲取平均值，參數是要統計的字段名（必填）

//靜態調用
User::avg('score');
User::where('status','>',0)->avg('score');

//動態調用
$user = new User;
$user->avg('score');
$user->where('status','>',0)->avg('score');

5、sum 獲取總分，參數是要統計的字段名（必填）

//靜態調用
User::sum('score');
User::where('status','>',0)->sum('score');

//動態調用
$user = new User;
$user->sum('score');
$user->where('status','>',0)->sum('score');