更新记录的日期比较

I'm getting records from a MySQL database with this PHP function:

function someFunction($date){
    // all distinct records
    $query = "select count(distinct column_name) as alias from table_name where DATE(date_column) = '$date'";
    $result = $connection->query($query);
    $row = $result->fetch_assoc();
    return $row['alias'];
    // end of all distinct records
} 

Now what the below PHP code does is, get the day in the date, compute the week of the month it belongs to and stores it an an array.

//while fetch_assoc returns records
//$result1 query: "select * from table_name where DATE(date) between '$first_date' and date_add('$end_date',interval 1 day)"

while ($row1 = $result1->fetch_assoc()) {
  $date = $row1['date'];
  $start = 1;
  $end = 7;
  for ($i = 1; $i <= 5; $i++) {
    if ((int) date('d', strtotime($date)) >= $start && (int) date('d', strtotime($date)) <= $end) {
      if (!isset($arr1[$i]) || !isset($arr2[$i])) {
        $arr1[$i] = 0;
        $arr2[$i] = 0;
      }
      ++$arr1[$i];

      $arr2[$i] = someFunction(date('Y-m-d', strtotime($date)));
    }
    $start += 7;
    $end += 7;
  }
}

Consider 1st, 2nd and 3rd belong to the same week, 1st has 3 records, 2nd has 4 and 3rd has 1. The while loop will iterate 7 times, each value returned by the someFunction() overwriting the value in $arr2[$i].

So my question is, how will I be able to check if the previous iteration date value is equal to the current date value?

So my question is, how will I be able to check if the previous iteration date value is equal to the current date value?

Pseudocode:

$lastValue = …; // initialization with a value that does not occur in the actual values,
                // such as NULL, empty string, …

while(…) {
  if($currentValue == $lastValue) {
    // do something
  }
  else {
    // do something else
  }

  // …

  $lastValue = $currentValue; // set current value for next loop interation
}