PHP/MYSQL : get unlimited data - php

Question

i have a large data in my mysql database (500 rows), when i am trying to get all of them , the data is not coming from database.
Working Code
<?php
include '../db/db.php';
$categoriesDataQuery = mysqli_query($conn, "SELECT * FROM subcategories LIMIT 268");
while ($row = mysqli_fetch_assoc ($categoriesDataQuery)) {
$categoryData [] = $row;
}
$categoryNewData = $categoryData;
print (json_encode ($categoryNewData)) ;
mysqli_close ($conn);
?>
Not Working Code
<?php
include '../db/db.php';
$categoriesDataQuery = mysqli_query($conn, "SELECT * FROM subcategories");
while ($row = mysqli_fetch_assoc ($categoriesDataQuery)) {
$categoryData [] = $row;
}
$categoryNewData = $categoryData;
print (json_encode ($categoryNewData)) ;
mysqli_close ($conn);
?>
Maybe Mysql database have some limitation when user select a large data ?!
Who ever encountered this?

Answer 1

The problem is not with the SQL query or the amount of data that you're trying to encode. For some reason, json_encode can return an empty string instead of throwing an error when it encounters an invalid character.
You have to make sure that the SQL connection's charater encoding matches your database table's encoding. For example if you're using UTF-8 encoding on your table, you need to call the following function to force the same encoding on the PHP client:
mysqli_set_charset($conn, "utf8");
See the PHP docs for more information.