在PHP我需要一行如果条件的时间比较

Question

i have to value

 $mo=strtotime($input_array['MondayOpen']);
 $mc=strtotime($input_array['MondayClose']);

now i need a if condition to display an error on below conditions

1. if one of them($mo or $mc) are empty, null or blank.
2. if close time($mc) is less than open time($mo)

means if both are empty(null) or $mc>$mo then go further

please suggest optimized one line if condition for this

i know it seems very basic question, but i m facing problem when both are null either i was using simple

if(($mo==NULL && $mc!=NULL) || ( $mo>=$mc && ($mo!=NULL && $mc!=NULL))  )

Answer 1

in php, strotime will return a integer or false. Checking for null in this case will never bear fruit, but otherwise...

if((!$mo xor !$mc) || ($mc && $mc<=$mo)){
  print('error');
}else{
 print('no_error');
}

oops, edited for correctness. I transposed $mc and $mo. XOR should be correct though.