How to encode fetched data from MySQL to JSON via PHP

Question

I'm trying to encode data coming from Mysql database into JSON format via PHP.Here's the code segment:

try
{
    $statement = $db->prepare($query);
    $result = $statement->execute($query_params);

    $rows = $statement->fetchAll();

    echo print_r($rows)."<br/>";

    foreach($rows as $row)
    {
        foreach($row as $a)
    {
        $studentInfo = array();
        $studentInfo["course"] = $a["coursename"];
        $studentInfo["grade"] = $a["grade"];
        array_push($response['info'], $studentInfo);
    }
    }
    echo json_encode($response);
}

But I'm not able to encode this array into JSON. The print_r($rows) prints the following:

Array (
    [0] => Array (
        [id] => 22222
        [coursename] => sp1
        [grade] => B
    )
    [1] => Array (
        [id] => 22222
        [coursename] => sw1
        [grade] => A-
    )
    [2] => Array (
        [id] => 22222
        [coursename] => sw2
        [grade] => B+
    )
)
1

And echo json_encode($response) prints the following:

{"info":null}

Could anyone please show me how to parse this array into JSON? I would like to get to each course and its grade in JSON format.

Remove the inner loop. $row has the contents you are looking for instead of $a — datasage
– datasage, Commented Feb 25, 2014 at 1:00
or just json_encode(array('info'=>$rows)) from your original $rows ... no need for any of the loops.. — CrayonViolent
– CrayonViolent, Commented Feb 25, 2014 at 1:08
Thanks datasage. Removing the inner loop solved the porblem!!! — Zak
– Zak, Commented Feb 26, 2014 at 16:00

sharif2008 · Accepted Answer · 2014-02-26 16:22:41Z

try
{
    $statement = $db->prepare($query);
    $result = $statement->execute($query_params);

    $rows = $statement->fetchAll();

    echo print_r($rows)."<br/>";

    $response=array();
    $info=array();

    foreach($rows as $row)
    {      
        $studentInfo = array();
        $studentInfo["id"]=$row["id"];
        $studentInfo["course"] = $row["coursename"];
        $studentInfo["grade"] = $row["grade"];
        array_push($info, $studentInfo);    
    }

    $response['info']=$info;
    echo json_encode($response); // or echo json_encode($info);// whatever you want
 }

Leonardo Chaia · Accepted Answer · 2014-02-25 01:31:00Z

1

I'd do something like this:

try {
    $statement = $db->prepare($query);
    $result = $statement->execute($query_params);
    if($result) {
        $arr = Array();
        while ($row = $result->fetch_assoc()) {
            $arr[] = $row;
        }
     echo json_encode($arr);
    }
}

answered Feb 25, 2014 at 1:31

Leonardo Chaia

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Comments

Kevin Khew · Accepted Answer · 2016-02-10 04:57:26Z

0

json_encode() can directly encode the array.

at your code line 8, can do this

echo json_encode($rows);

Please click here to refer for more info http://php.net/manual/en/function.json-encode.php

<?php
$arr = array('a' => 1, 'b' => 2, 'c' => 3, 'd' => 4, 'e' => 5);

echo json_encode($arr);
?>

Output:
{"a":1,"b":2,"c":3,"d":4,"e":5}

answered Feb 10, 2016 at 4:57

Kevin Khew

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