Datatables not sorting date correctly Serverside - mysql

Question

I am using server side processing, so as I understand, all sorting/ordering is done server side. However, when I click on the column header, it should send the server a post variable to apply the ASC or DESC sort order. This is not working and I'm trying to figure out where my problem lies.
I am using the default script that comes with datatables.
My dates in the database is stored as timestamp values such as 15-10-2015 10:20:30.
Now, the table displays fine, however the dates are not sorted correctly. Even if I output just the year values e.g. 2014 , it does not sort them ASC and DESC.
Instead, I get results like:
2014
2014
2015
2015
2014
2014
2015
:(
I declare the table as follows :
DemoTable = $('#table_demo').DataTable(
{
"order": [],
"aaSorting" : [],
"deferRender": true,
"bJQueryUI": true,
"bPaginate": true,
"bStateSave": true,
"processing": true,
"serverSide": true,
"sPaginationType": "full_numbers",
"ajax":
{
"url": "view_demo_remote.php",
"data":
{
"role": $_SESSION['role'],
"email": $_SESSION['email'],
"practiseid": $_SESSION['practiceid']
}
},
"columns":[
{ "data": "first_number" , "bSortable": true },
{ "data": "datecreated", "bSortable": true },
{ "data": "submitted_by"},
{ "data": "second_number"},
{ "data": "picture","bSortable": false },
{ "data": "options","bSortable": false }
],
});
On the server, I have the following section for the columns:
$columns = array(
array(
'db' => 'id',
'dt' => 'DT_RowId',
'formatter' => function( $d, $row )
{
// Technically a DOM id cannot start with an integer, so we prefix
// a string. This can also be useful if you have multiple tables
// to ensure that the id is unique with a different prefix
return $d;
}
),
array(
'db' => 'firstnumber',
'dt' => 'first_number',
'formatter' => function($d, $row)
{
$number = $d;
return substr($number, 0, 10);
}),
array(
'db' => 'datecreated',
'dt' => 'datecreated',
'formatter' => function($d, $row)
{
// DD/MM/YYYY HH:MM:SS
$date = date_create_from_format('d-m-Y H:i:s', $d);
return date_format($date, 'Y');
}),
array( 'db' => 'username', 'dt' => 'submitted_by' ),
array( 'db' => 'secondnumber', 'dt' => 'second_number' ),
array(
'db' => 'picture',
'dt' => 'picture',
'formatter' => function($d, $row)
{
return "<p style=\"padding:5px;\"><img src=\"".$d."\" alt=\"Picture\" style=\"width:auto;max-height:70px;border:1px solid #2d2d2d;-webkit-border-radius: 5px;-moz-border-radius: 5px;border-radius: 5px; \"></img></p>";
}),
array( 'db' => 'id', 'dt' => 'options');
);
and then I have this part after the columns section:
// SQL server connection information
$sql_details = array(
'user' => DBUSER,
'pass' => DBUSERPASS,
'db' => DBNAME,
'host' => DBHOST
);
require( 'libraries/DataTables-1.10.7/examples/server_side/scripts/ssp.class.php' );
$whereAll = " firstnumber <>''";
echo json_encode(SSP::complex( $_GET, $sql_details, $table, $primaryKey, $columns, "",$whereAll));
So the table displays fine, all column headers for the sortable columns can be clicked on and it sorts ASC or DESC perfectly. However, the date does not sort perfectly. If I turn off sorting off on the table and I manually add "ORDER BY datecreated ASC" to the where clause, it works perfectly, which tells me that there is nothing wrong with my date format, however, I want sorting ON.
Please help
I have also asked a question on the datatables forums https://www.datatables.net/forums/discussion/31216/datatables-not-ordering-date-correctly

Answer 1

Thanks all for contributing.
At the end of the day, the problem was actually caused by a field in the database that was in the wrong format. The datecreated field was saved as a Varchar and it had to be DATETIME.
Once I fixed this in the database, everything sorted perfectly.
thanks for everyone who helped. But yes, I want to stress the fact that when server side processing is being done, all sorting / ordering is done server side. You can manipulate the format and display on the client side, but NOT the actual order, when server side is being used.