laravel Compare mysql column string date

 $previousMonthFirstDate = date("d/m/Y", mktime(0, 0, 0, date("m")-1, 1));

// dd($previousMonthFirstDate);

$lastMonth = date('m')-1;

$currentMonth = date('m');

$monthDays=[31,28,31,30,31,30,31,31,30,31,30,31];

$currentMonthlastDate = date("d/m/Y",mktime(0,0,0,date("m"),$monthDays[$currentMonth-1]));

$billdate_raw = DB::raw("STR_TO_DATE(`bill_date`, '%d/%m/%Y')");

$start_raw = DB::raw("STR_TO_DATE(?, '%d/%m/%Y')");

$end_raw = DB::raw("STR_TO_DATE(?, '%d/%m/%Y')");

$authUser=Auth::user()->user_id;

$tableRecords = DB::table($table)

->where($billdate_raw,'>=',$start_raw)

->where($billdate_raw,'<=',$end_raw)

->where('user_id',$authUser)

->setBindings([$previousMonthFirstDate, $currentMonthlastDate,$authUser])

->orderBy('id','DESC')

->get();

return $tableRecords;