Form json using php json_encode failed - php

Question

By using below code
$data = array();
$sql = "SELECT * FROM list";
$result = $db->query($sql);
if ($result->num_rows > 0) {
while($row = $result->fetch_assoc()) {
$data['title'] = $row['title'];
$data['name'] = $row['name'];
}
}
echo json_encode($data);
I got 1 result, I can get full result if I do $data[] = $row['title'], but I want to make the result like this
{'title' : ['title 1','title 2'], 'name':['John','Amy']}

Answer 1

You are overwriting the title in each loop iteration. You need to accumulate all the titles and then set it in your data array.
$data = array();
$sql = "SELECT title FROM mainlist";
$result = $db->query($sql);
$titles = array();
if ($result->num_rows > 0) {
while($row = $result->fetch_assoc()) {
$titles[] = $row['title'];
}
}
$data['title'] = $titles;
echo json_encode($data);

Answer 2

The easiest away is probably this:
$rows = array();
$sql = "SELECT * FROM list";
$result = $db->query($sql);
if ($result->num_rows > 0) {
while($row = $result->fetch_assoc()) {
$rows[] = $row;
}
}
echo json_encode($rows);

Answer 3

you could achieve by using group_concat on each of the columns in your query. That way you do not need to loop the result again and add column etc...
$sql = "SELECT group_concat(title) as title,group_concat(name) as name FROM list";
$result = $db->fetch(PDO::FETCH_ASSOC);
echo json_encode($result);

Answer 4

Try this:
$titles = array();
$names = array();
$sql = "SELECT title,name FROM mainlist";
$result = $db->query($sql);
if ($result->num_rows > 0) {
while($row = $result->fetch_assoc()) {
$titles[] = $row['title'];
$names[] = $row['name'];
}
}
echo json_encode(array("title" => $titles, "name" => $names));
UPDATE
Updated my code to let you manage an undefined number of columns as result
$out = array();
$sql = "SELECT * FROM wp_cineteca";
$result = $db->query($sql);
if ($result->num_rows > 0) {
while($row = $result->fetch_array()) {
$keys = array_keys($row);
for ($i = 0; $i < count($row); $i++) {
$out[$keys[$i]][] = $row[$i];
}
}
}
echo json_encode($out);