How to call the custom function with the date returned from the database?

Question

Successfully fetch "wdate" from MySQL and print the date in format Y:m:d H:i:s, my goal is to input "wdate" in the second code "function" is this possible or completely wrong?

<?php 

$sql = "SELECT wdate, DATE_FORMAT(wdate,'%Y/%m/%d %H:%i:%s') AS wdate 
            FROM watering
            ORDER BY id 
            DESC limit 1";
$result = $conn->query($sql);

    if ($result->num_rows > 0) {
    // output data of each row
    while($row = $result->fetch_assoc()) {
$recoredDate = $row["wdate"];

            }
    } else {
      echo "<h1><b>Database is empty</b></h1>";
    }
?>

This is the second part calculating the difference like this:

<?php

 function time_elapsed_string($datetime, $full = false) {
    $now = new DateTime;
    $ago = new DateTime($datetime);
    $diff = $now->diff($ago);

    $diff->w = floor($diff->d / 7);
    $diff->d -= $diff->w * 7;

    $string = array(
        'y' => 'year',
        'm' => 'month',
        'w' => 'week',
        'd' => 'day',
        'h' => 'hour',
        'i' => 'minute',
        's' => 'second',
    );
    foreach ($string as $k => &$v) {
        if ($diff->$k) {
            $v = $diff->$k . ' ' . $v . ($diff->$k > 1 ? 's' : '');
        } else {
            unset($string[$k]);
        }
    }

    if (!$full) $string = array_slice($string, 0, 1);
    return $string ? implode(', ', $string) . ' ago' : 'just now'; }    ?>  



   <?php echo ($recoredDate);?> <!-- Result from Database -->
 <?php echo time_elapsed_string('2021-01-28 20:46:25'); ?> <!-- Result from function -->

Answer 1

The main question appears to be:

How to call the custom function with the date returned from the database?

The answer to which is replace this line...

$recoredDate = $row["wdate"];

...with this line...

echo time_elapsed_string($row["wdate"], true);

...if you simply want to output the difference.

Alternatively, with your code above...

echo time_elapsed_string($recoredDate, true);

Note: this assumes that the function and the code are in the same file/scope

Additional info

Let's assume that you have stored the wdate date in a DateTime field in your database. In that case the format is already Y-m-d H:i:s which is what you want to feed into your function, so we can just select it and not have to try and reformat it...

Updated code

I have updated your code with the appropriate query and output:

$sql = "
    SELECT wdate
    FROM watering
    ORDER BY id DESC
    LIMIT 1
";

$result = $conn->query($sql);

if($result->num_rows) {
    while($row = $result->fetch_assoc()){
        echo "Last watering: ", time_elapsed_string($row["wdate"], 1);
    }
}
else{
    echo "<h1><b>Database is empty</b></h1>";
}

I've also updated your function a bit:

function time_elapsed_string(string $inputTimestamp, bool $full = false) : string
{
    $currentTime    = new DateTime;
    $compareTime    = new DateTime($inputTimestamp);
    $timeDifference = $currentTime->diff($compareTime);

    $timeDifference->w  = floor($timeDifference->d / 7);
    $timeDifference->d %= 7;

    $datePartArray = [
        'y' => 'year',
        'm' => 'month',
        'w' => 'week',
        'd' => 'day',
        'h' => 'hour',
        'i' => 'minute',
        's' => 'second',
    ];

    $output = [];
    foreach($datePartArray as $datePart => $description){
        if($timeDifference->$datePart){
            $output[] = "{$timeDifference->$datePart} {$description}"
                        . ($timeDifference->$datePart > 1 ? 's' : '');
        }
    }

    if (!$full){
        $output = [ $output[0] ];
    }

    return $output ? implode(', ', $output) . ' ago' : 'just now'; 
} 

If wdate isn't in the right format then we're still just going to select it from the database as above and we'll amend the code in the function to accommodate...

Of course if this is the case then I don't know what format you have it in (you haven't said as yet) so you will have to amend as needed. But effectively we're going to change this line:

$compareTime    = new DateTime($inputTimestamp);

To something like:

// Date/Time: 15/01/2021 12:03
$compareTime = DateTime::createFromFormat("d/m/Y H:i", $inputTimestamp);

// Unix timestamp: 1610757655
$compareTime = DateTime::createFromFormat("U", $inputTimestamp);
// OR...
$compareTime = new DateTime("@".$inputTimestamp);