PHP JSON Array - Group by the same value

问题:

I'm thinking how to group my array by objects with the same value.

I have this result from MySQL query:

   Date           StartTime           EndTime
2014-12-01          08:00              12:00
2014-12-01          10:00              16:00
2014-12-02          12:00              18:00
2014-12-03          10:00              20:00

I have this data in a PHP variable called $Data.

Is it possible to get the json array like this with php: ?

[
    {
        "2014-12-01": [
            {
                "StartTime": "08:00",
                "EndTime": "12:00"
            },
            {
                "StartTime": "10:00",
                "EndTime": "16:00"
            }
        ]
    },
    {
        "2014-12-02": [
            {
                "StartTime": "12:00",
                "EndTime": "18:00"
            }
        ]
    },
    {
        "2014-12-03": [
            {
                "StartTime": "10:00",
                "EndTime": "20:00"
            }
        ]
    }
]

If I use echo json_encode($Data), the result is:

[
    {
        "Date": "2014-12-01",
        "StartTime": "10:00",
        "EndTime": "16:00"
    },
    {
        "Date": "2014-12-02",
        "StartTime": "12:00",
        "EndTime": "18:00"
    },
    {
        "Date": "2014-12-03",
        "StartTime": "10:00",
        "EndTime": "20:00"
    }
]

回答1:

Based on the structure outlined in the question:

Requires php 5.4+ for the json pretty printing, if you are on a lower version just remove it and use long array format.

$in = <<<'JSON'
[
    {
        "Date": "2014-12-01",
        "StartTime": "10:00",
        "EndTime": "16:00"
    },
    {
        "Date": "2014-12-02",
        "StartTime": "12:00",
        "EndTime": "18:00"
    },
    {
        "Date": "2014-12-03",
        "StartTime": "10:00",
        "EndTime": "20:00"
    },
    {
        "Date": "2014-12-03",
        "StartTime": "12:00",
        "EndTime": "20:00"
    }
]
JSON;

$data = json_decode($in, true);
$out = [];

foreach($data as $element) {
        $out[$element['Date']][] = ['StartTime' => $element['StartTime'], 'EndTime' => $element['EndTime']];
}

var_dump(json_encode($out, JSON_PRETTY_PRINT));

To get the exact same output as in the question (the returned output wrapped in a single element json-array you'd need to wrap $out in an other array like this:

json_encode([$out], JSON_PRETTY_PRINT)

Results in:

{
  "2014-12-01": [
    {
      "StartTime": "10:00",
      "EndTime": "16:00"
    }
  ],
  "2014-12-02": [
    {
      "StartTime": "12:00",
      "EndTime": "18:00"
    }
  ],
  "2014-12-03": [
    {
      "StartTime": "10:00",
      "EndTime": "20:00"
    },
    {
      "StartTime": "12:00",
      "EndTime": "20:00"
    }
  ]
}

回答2:

EMPLOYER NAME DATA_PATH Alp 1. video_link 2. video_link Xyz 1. video_link 2. video_link 3. video_link

$stmt = $this->conn->prepare("SELECT a.employer_name,b.data_path FROM 
rec_experience a INNER JOIN rec_multi_upload_data b 
ON(a.rec_uniqueid=b.rec_id) WHERE b.data_type='Video'  ORDER BY 
a.c_date DESC ");
$stmt->execute();
$res = $stmt->fetchAll(PDO::FETCH_ASSOC);

$out = [];

foreach($res as $element)
{
 $out[$element['employer_name']][] = ['video_link' => 
 $element['data_path']];
}
echo json_encode($out);