如何使用PHP偏移HTML表以从不同列的第二行单元格值中减去第一行的单元格值

Question

OK, so I'm trying to solve this problem from last week and haven't found a solution yet I ask the Question so many times but not able to get the Code working so I'm putting all details in this one Question.

I'm Generating an HTML table with PHP and Mysql query (Table look like this Table )

DB ID   EmpID   Date        Username    Computername    State   Minutesatstate  Statestarttime  Stateendtime        Timestamp
704634  303836  02-06-2019  user        PC-818          Idle    2               13:44           13:46               2019-02-06 13:46:46
704599  303836  02-06-2019  user        PC-818          Active  16              13:28           13:44               2019-02-06 13:44:46
704340  303836  02-06-2019  user        NIPL-1220       Active  2               13:27           13:28               2019-02-06 13:28:48
704313  303836  02-06-2019  user        PC-818          Active  13              13:15           13:27               2019-02-06 13:27:31

I want to add another column with PHP or Jquery or Javascript to subtract Statestarttime column of 1st row with Stateendtime column of 2nd row to find out the time difference.

I just want min difference column to be displayed on the page.

example of expected results

StateStarTtime    StateEndTime   Min Difference 

03:57             03:58          00:03
03:53             03:54          00:04
03:46             03:49          null

I'm able to find so many example and help for subtracting StateStarTtime from StateEndTime in the first row but i want to subtract 1st row cell value of StateStarTtime from 2nd row cell value of StateEndTime to find the Minute Difference.

I'm beginner in HTML and PHP but completely new to JS/JQ so any direction on how i can do this is much appreciated. Below are the PHP and HTML codes snippet i'm using. Let me know if you want complete code.

Geting data from Mysql

<?php

if(isset($_POST['search']))
{
    $valueToSearch = $_POST['valueToSearch'];
    $query = "SELECT * FROM time WHERE DATE_SUB(CURDATE(),INTERVAL 7 DAY) <= Timestamp AND EmpID='".$valueToSearch."' ORDER BY `time`.`Timestamp` DESC";
    $search_result = filterTable($query);

}
 else {
    $query = "SELECT * FROM time WHERE DATE_SUB(CURDATE(),INTERVAL 1 DAY) <= Timestamp ORDER BY `time`.`Timestamp` DESC";
    $search_result = filterTable($query);
}

function filterTable($query)
{
    $connect = mysqli_connect("localhost", "root", "", "timetracker");
    $filter_Result = mysqli_query($connect, $query);
    return $filter_Result;
}

?>

Table PHP Code

            <?php while($row = mysqli_fetch_array($search_result)):?>

            <tr>
                <td align="Center"><?php echo $row['id'];?></td>
                <td align="Center"><?php echo $row['EmpID'];?></td>
                <td align="Center"><?php echo $row['Date'];?></td>
                <td align="Center"><?php echo $row['Username'];?></td>
                <td align="Center"><?php echo $row['Computername'];?></td>
                <td align="Center"><?php echo $row['State'];?></td>
                <td align="Center"><?php echo $row['MinutesatState'];?></td>
                <td align="Center"><?php echo $row['StateStarttime'];?></td>
                <td align="Center"><?php echo $row['StateEndtime'];?></td>
                <td align="Center"><?php echo $row['Timestamp'];?></td>


            </tr>
            <?php endwhile;?>

tried solutions - 1

<?php while($row = mysqli_fetch_array($search_result)):?>
    <?php $startTime[] =  $row['StateStarttime'];?>
    <?php $endTime[] = $row['StateEndtime'];?>
<?php endwhile;?>
<?php 
    $i = 0;
    while($row = mysqli_fetch_array($search_result)):?>
        <tr>
            <td align="Center"><?php echo $row['id'];?></td>
            <td align="Center"><?php echo $row['EmpID'];?></td>
            <td align="Center"><?php echo $row['Date'];?></td>
            <td align="Center"><?php echo $row['Username'];?></td>
            <td align="Center"><?php echo $row['Computername'];?></td>
            <td align="Center"><?php echo $row['State'];?></td>
            <td align="Center"><?php echo $row['MinutesatState'];?></td>
            <td align="Center"><?php echo $row['StateStarttime'];?></td>
            <td align="Center"><?php echo $row['StateEndtime'];?></td>
            <td align="Center"><?php echo $row['Timestamp'];?></td>
            //your calculation goes here like diff



            <td align="Center">
               <?php 
                   $mycalc = ($startTime[$i] - $endTime[$i+1]);   
                    echo $mycalc;
                ?>
            </td>
        </tr>
        $i++;
<?php endwhile;?>

tried solutions - 2

<?php for($i = 0; $i < count($results); $i++): ?>
    <?php
    $datetime1 = DateTime::createFromFormat('i:s', $results[$i]['StateStarttime']);
    $datetime2 = DateTime::createFromFormat('i:s', $results[$i+1]['StateEndtime']);

    if($datetime2)
        $interval = $datetime1->diff($datetime2)->format('%I:%S');
    else
        $interval = 'unknown';

    ?>
    <tr>
        <td align="Center"><?php echo $results[$i]['id'];?></td>
        <td align="Center"><?php echo $results[$i]['EmpID'];?></td>
        <td align="Center"><?php echo $results[$i]['Date'];?></td>
        <td align="Center"><?php echo $results[$i]['Username'];?></td>
        <td align="Center"><?php echo $results[$i]['Computername'];?></td>
        <td align="Center"><?php echo $results[$i]['State'];?></td>
        <td align="Center"><?php echo $results[$i]['MinutesatState'];?></td>
        <td align="Center"><?php echo $results[$i]['StateStarttime']; ?></td>
        <td align="Center"><?php echo $results[$i]['StateEndtime']; ?></td>
        <td align="Center"><?php echo $results[$i]['Timestamp'];?></td>
        <td align="Center"><?php echo $interval; ?></td>

    </tr>
<?php endfor; ?>

Before Anyone suggest me this

<td align="Center"><?php echo($row['StateEndtime'] - $row['StateStarTtime ']) ?></td>

This will give me the Minute Difference of StateStarTtime and StateEndtime in the same row i want to subtract 1st row cell value of StateStarTtime from 2nd row cell value of StateEndTime and so on to find the Minute Difference.

Answer 1

Try something along the lines of this. Only a guideline, the real implementation is up to you. Also I'd recommend you use {} rather than endwhile .

   <?php 
    $last_row = $mysqli_fetch_array($search_result));
    while($row = mysqli_fetch_array($search_result)){
    //this is pseudocode, you will need to convert to date objects
    $timediff = $last_row['StateStarttime'] - $row['StateEndtime'];
    ?>
        <tr>
            <td align="Center"><?php echo $row['id'];?></td>
            <td align="Center"><?php echo $row['EmpID'];?></td>
            <td align="Center"><?php echo $row['Date'];?></td>
            <td align="Center"><?php echo $row['Username'];?></td>
            <td align="Center"><?php echo $row['Computername'];?></td>
            <td align="Center"><?php echo $row['State'];?></td>
            <td align="Center"><?php echo $row['MinutesatState'];?></td>
            <td align="Center"><?php echo $row['StateStarttime'];?></td>
            <td align="Center"><?php echo $row['StateEndtime'];?></td>
            <td align="Center"><?php echo $row['Timestamp'];?></td>
            // echo $timediff
        </tr>
        <?php
        $last_row = $row;
    }?>