ThinkPHP5.0 模型聚合操作

1、count 统计数量，参数是要统计的字段名（可选填）

//静态调用
User::count();
User::where('status','>',0)->count();

//动态调用
$user = new User;
$user->count();
$user->where('status','>',0)->count();

2、max 获取最大值，参数是要统计的字段名（必填）

//静态调用
User::max('score');
User::where('status','>',0)->max('score');

//动态调用
$user = new User;
$user->max('score');
$user->where('status','>',0)->max('score');

3、min 获取最小值，参数是要统计的字段名（必填）

//静态调用
User::min('score');
User::where('status','>',0)->min('score');

//动态调用
$user = new User;
$user->min('score');
$user->where('status','>',0)->min('score');

4、avg 获取平均值，参数是要统计的字段名（必填）

//静态调用
User::avg('score');
User::where('status','>',0)->avg('score');

//动态调用
$user = new User;
$user->avg('score');
$user->where('status','>',0)->avg('score');

5、sum 获取总分，参数是要统计的字段名（必填）

//静态调用
User::sum('score');
User::where('status','>',0)->sum('score');

//动态调用
$user = new User;
$user->sum('score');
$user->where('status','>',0)->sum('score');