MySQL to JSON, how to get the right format?

Question

So, I'm using a PHP-script to output MySQL to JSON, but I'm having trouble figuring out how to output the right JSON-format.

Here's the PHP-script:

$sql_query = "SELECT * FROM DiseaseData"; 
$res_sql = mysql_query($sql_query) or die(mysql_error());
$arr = array();


if(mysql_num_rows($res_sql) > 0){   

    ini_set('memory_limit', '-1');
    while($row_sql = mysql_fetch_assoc($res_sql)){

        $arr[] =  $row_sql;

        }
        $json = json_encode($arr);
        $file = '../../files/json/DiseaseData.json';
        file_put_contents($file, $json);

    }  
    ini_set('memory_limit', '-1');

Here's the outputted JSON-format:

[{
    "ID": "1",
    "Magnitude": "0.842",
    "County": "Alameda",
    "Disease": "E. coli O157",
    "lat": "37.7652",
    "lng": "-122.242"
}, {
    "ID": "2",
    "Magnitude": "1.520",
    "County": "Alameda",
    "Disease": "HIV",
    "lat": "37.7652",
    "lng": "-122.242"
}]

This is the JSON-format I'd like to have it in:

{
    "columns":[{
            "fieldName" : "ID",
            "position" : 1
    },
    {
            "fieldName" : "Magnitude",
            "position" : 2
    },
    {
            "fieldName" : "County",
            "position" : 3
    },
    {
            "fieldName" : "Disease",
            "position" : 4
    },
    {
            "fieldName" : "lat",
            "position" : 5
    },
    {
            "fieldName" : "lng",
            "position" : 6
    },]
    "data": [ 
        [ 1, 0.842, "Alameda", "E. coli O157", 37.7652, -122.242],
        [ 2, 1.520, "Alameda", "HIV", 37.7652, -122.242]
    ]
}

score 1 · Accepted Answer · edited May 23 '17 at 12:31

The solution would be like this:

Create two arrays, $columns and $data
In $columns array, store the position and the associated field name
In $data array, insert all data rows using while loop.
Finally, insert both the arrays in $result array and then apply json_enocde() on it.

Here's the code:

// your code

if(mysql_num_rows($res_sql) > 0){   
    $columns = $data = array();
    $max_columns = mysql_num_fields($res_sql);

    for($i=0; $i < $max_columns; $i++){
         $columns[] = array('fieldName' => mysql_field_name($res_sql, $i), 'position' => $i+1);
    }

    while($row_sql = mysql_fetch_assoc($res_sql)){
        $data[] =  array_values($row_sql);
    }
    $result = array('columns' => $columns, 'data' => $data);
    $json = json_encode($result);

    // your code  
}

Note: Don't use mysql_* functions, they are deprecated as of PHP 5.5 and are removed altogether in PHP 7.0. Use mysqli or pdo instead. And this is why you shouldn't use mysql_* functions.

Thanks, seems to be working like charm! Only thing was that the column "ID" returned boolean "false" in the outputted JSON and the columns switched position. `"columns": [{ "fieldName": "Magnitude", "position": 1 }, { "fieldName": "County", "position": 2 }, { "fieldName": "Disease", "position": 3 }, { "fieldName": "lat", "position": 4 }, { "fieldName": "lng", "position": 5 }, { "fieldName": false, "position": 6 }]` — Adam, Jun 19 '16 at 17:49
@AdamDedanga Oh, that's because of the `for` loop, it should be `for($i=0; $i < $max_columns; $i++){...`, and instead of `'position' => $i`, it should be `'position' => $i+1`. I've updated my answer. — Rajdeep Paul, Jun 19 '16 at 17:51

MySQL to JSON, how to get the right format?

1 Answers1