Использование Eloquent модели:
$records = TsData::select(
'employee',
'workdate',
\DB::raw('sum(actualhours) as sumhours')
)
->groupBy('employee', 'workdate')
->get();
или использование фасада БД:
$records = \DB::table('ts_data')->select(
'employee',
'workdate',
\DB::raw('sum(actualhours) as sumhours')
)
->groupBy('employee', 'workdate')
->get();