How to reformat JSON response using values from Array - php

Question

Essentially I have the following script with the following response:
<?php
header('Content-Type: application/json');
$stmt = $pdo->prepare('
SELECT
`tablelist`.`id`,
`tablelist`.`content`
FROM `tablelist `
');
$stmt->execute([
]);
$row = $stmt->fetchAll(PDO::FETCH_ASSOC);
$rowcount = $stmt->rowCount();
if ($rowcount < 1) {
$response["error"] = TRUE;
echo json_encode($response);
}else{
echo json_encode($row);
}
?>
Current Response:
[
{
"id": 1,
"content": "Reason 1"
},
{
"id": 2,
"content": "Reason 2"
},
{
"id": 3,
"content": "Reason 3"
},
{
"id": 4,
"content": "Reason 4"
}
]
I would instead like to present this array as the following (no square brackets):
{
"error": false,
"content": {
"1": "Reason 1",
"2": "Reason 2",
"3": "Reason 3",
"4": "Reason 4"
}
I know I need to do the following:
$response["error"] = FALSE;
$response["content"][$row[id]] = $row[content];
But using this method I am not getting any values from the array.
How can present the values from the array the way?

Answer 1

Look at array_column function and Example #2 at https://www.php.net/manual/en/function.array-column.php
You can transform your rows like this but you must be aware of the uniqueness
$content = '[
{
"id": 1,
"content": "Reason 1"
},
{
"id": 2,
"content": "Reason 2"
},
{
"id": 3,
"content": "Reason 3"
},
{
"id": 4,
"content": "Reason 4"
}
]';
$from = json_decode($content, true);
$to = json_encode(array_column($from, 'content', 'id'), JSON_PRETTY_PRINT);
echo $to;
will result to
{
"1": "Reason 1",
"2": "Reason 2",
"3": "Reason 3",
"4": "Reason 4"
}
via https://3v4l.org/WL29a

Answer 2

You can do it very easily with PDO using the PDO::FETCH_KEY_PAIR fetch mode. It will use the first column from SQL as a key and the second as the value.
<?php
header('Content-Type: application/json');
$stmt = $pdo->prepare('
SELECT
`tablelist`.`id`,
`tablelist`.`content`
FROM `tablelist `
');
$stmt->execute();
$dataFromDB = $stmt->fetchAll(PDO::FETCH_KEY_PAIR);
if (!$dataFromDB) {
echo json_encode(['error' => true]);
} else {
echo json_encode(['error' => false, 'content' => $dataFromDB]);
}
This will produce an output similar to this if there were any rows returned from the SELECT:
{
"error": false,
"content": {
"1": "Reason 1",
"2": "Reason 2",
"3": "Reason 3",
"4": "Reason 4"
}
}