创建一个JSON数组对象 - 按相同日期分组到一个新数组？

I'm thinking how to group my array by objects with the same date. I have this result from MySQL query(select DateTime ,ip,Val from my table):

  DateTime                 ip                       Val
2017-02-01 08:00:23       10.10.10.1                2
2017-02-01 09:01:23       10.10.10.2                3
2017-02-01 12:02:23       10.10.10.3                4
2017-02-02 13:03:23       10.10.10.4                5
2017-02-03 15:04:23       10.10.10.5                6
2017-02-03 20:05:23       10.10.10.6                7

from mysql query result to create json array object as below ,

$sql = "select DateTime ,ip,Val from my table order by DateTime ASC ;";
$result = $db->query($sql);
$data = array();
$rowary = array();
$i=0;
while($row = mysqli_fetch_array($result))
 {
    $rowary['DateTime'] = $row['DateTime '] ;
    $rowary['ip'] = $row['ip'] ;
    $rowary['Val'] = $row['Val'] ;
    $data[$i++]=$rowary;
  }
echo '<pre>' . var_export($data, true) . '</pre>';

Is it possible to create a JSON array object that group by the same date If I use

var data = <?php echo json_encode($Data, JSON_PRETTY_PRINT);?> 

in javascript,

expected result is:

 [
    [
      {
         "DateTime": "2017-02-01 08:00:23",
         "ip": "10.10.10.1",
         "Val": "2"
      },
      {
         "DateTime": "2017-02-01 09:01:23",
         "ip": "10.10.10.2",
         "Val": "3"
      },
      {
         "DateTime": "2017-02-01 12:02:23",
         "ip": "10.10.10.3",
         "Val": "4"
      }
   ],
   [
     {
        "DateTime": "2017-02-02 13:03:23",
        "ip": "10.10.10.4",
        "Val": "5"
     }
   ],
   [
    {
       "DateTime": "2017-02-03 15:04:23",
       "ip": "10.10.10.5",
       "Val": "6"
    },
    {
       "DateTime": "2017-02-03 20:05:23",
       "ip": "10.10.10.6",
       "Val": "7"
    }
   ]

 ]

How can I create a JSON array object that group by the same date?

Get data from mySQL in asc or dsc order, Then do like this:-

$a = array(
    array(
        'DateTime' => '2017-02-01 08:00:23',
        'ip'       => '10.10.10.1',
        'Val'       => '1'
    ),
    array(
        'DateTime' => '2017-02-01 09:01:23',
        'ip'       => '10.10.10.2',
        'Val'       => '2'
    ),
    array(
        'DateTime' => '2017-02-02 09:01:23',
        'ip'       => '10.10.10.3',
        'Val'       => '3'
    ),
    array(
        'DateTime' => '2017-02-02 13:03:23',
        'ip'       => '10.10.10.4',
        'Val'       => '4'
    ),
    array(
        'DateTime' => '2017-02-03 15:04:23',
        'ip'       => '10.10.10.5',
        'Val'       => '5'
    ),
    array(
        'DateTime' => '2017-02-03 20:05:23',
        'ip'       => '10.10.10.6',
        'Val'       => '6'
    ),
);

$FirstDate = date('Y-m-d', strtotime($a[0]['DateTime']));
$output = array();
$i = 0;

foreach($a as $value){

    $currentDate = date('Y-m-d', strtotime($value['DateTime']));

    if($currentDate != $FirstDate){
        $i++;
        $FirstDate = $currentDate;
    }       

    $output[$i][] = $value;

}

var_dump($output);

This could be in Javascript

You can use UnderscoreJS library for this refer http://underscorejs.org/#groupBy

You can do like this

"var a = [ { 'DateTime' :'2017-02-01 08:00:23', 'ip' :'10.10.10.1', 'Val' : '1' },

     {
    'DateTime' :'2017-02-01 09:01:23',
    'ip'       :'10.10.10.2',
    'Val'      : '2'
     },

     {
    'DateTime' :'2017-02-02 09:01:23',
    'ip'       :'10.10.10.3',
    'Val'      : '3'
    },

     {
    'DateTime' :'2017-02-02 13:03:23',
    'ip'       :'10.10.10.4',
    'Val'      : '4'
    },

     {
    'DateTime' :'2017-02-03 15:04:23',
    'ip'       :'10.10.10.5',
    'Val'      : '5'

    },

     {
    'DateTime' :'2017-02-03 20:05:23',
    'ip'       :'10.10.10.6',
    'Val'      : '6'
    }];

Then user _.groupBy function like this

_.groupBy(a, function(obj){ return new Date(obj.DateTime).toDateString() });"

Hope it will help you