How to convert MySQL TIMESTAMP to date time in PHP

Question

I have a MySQL DB table with a column named "timestamp", a type of timestamp, and attribute of on update CURRENT_TIMESTAMP and a default of CURRENT_TIMESTAMP.

If I add a record to the table, specifying other values, but not the timestamp, then the timestamp is automatically added like 2016-12-28 17:02:26.

In PHP I query the table using the following query

SELECT * FROM history WHERE user_id = 9 ORDER BY timestamp ASC

The result of the query is saved into $rows and I use a foreach to create an array with some of the other values formatted. I am attempting to format the time stamp to UK type 24-hour date time: dd/mm/yy, HH:MM:SS.

I have tried both the date() and strftime() functions as follows:

$formatted_datetime = strftime("%d %m %y  %H %M %S", $row["timestamp"]); 
$formatted_datetime = date("d/m/y, H:i:s", $row["timestamp"]);

Both of these result in the following notice and the date time being output incorrectly like 01 01 70 00 33 36:

Notice: A non well formed numeric value encountered in /home/ubuntu/workspace/pset7/public/history.php on line 20

I am new to PHP and MySQL and so far none of the other questions or documentation I have seen have successfully addressed performing this conversion.I do not understand why strftime() does not work, nor how to do this properly?

Answer 1

To do this the OO (and most flexible) way use DateTime class and use the static createFromFormat method to instantiate a new DateTime object:

$new_datetime = DateTime::createFromFormat ( "Y-m-d H:i:s", $row["timestamp"] );

Now you can use the $new_datetime object to generate any string representation you'd like by calling the object's format method:

echo $new_datetime->format('d/m/y, H:i:s');

To boot, you since you've a DateTime object you can now also to any manner of transformation (like shifting timezones or adding days), comparison (greater or less than another DateTime), and various time calculations (how many days/months/etc... between this and another DateTime).

DateTime:http://php.net/manual/en/class.datetime.php Learn it. Love it. Live it.