UTF8 in MySQL != UTF8 in PHP? [duplicate] - php

Question

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UTF-8 all the way through
(13 answers)
Closed 7 years ago.
So I was having an issue with json_encode returning null that I found the solution for here, but I don't understand why it was an issue in the first place. The MySQL tables from which I was drawing the data are defined like
CREATE TABLE `super_table` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(100) DEFAULT NULL,
`values` text,
`created` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
so shouldn't values and name be utf8 encoded already when I pull them out in PHP? A simplified version of what I'm doing:
$sql = "SELECT * FROM super_table";
$query = $mysqli->query($sql);
$data = (object) $query->fetch_all(MYSQLI_ASSOC);
foreach ($data as $key => $val) {
$data->$key = utf8_encode($val);
}
$result = array('success'=>$success, 'data'=>$data);
echo json_encode($result);
Why does not doing the extra utf8_encode step sometimes yield a null result when I try to json_encode it?

Answer 1

Indeed, MySQL's utf8 is not universally understood UTF-8. Even though this is not your issue here... MySQL's utf8 is a subset of actual UTF-8 only covering the BMP and not supporting 4-byte characters. But this just means that high characters will get discarded; otherwise it's still UTF-8 compatible.
Your actual issue is that MySQL is just storing the data in utf8, but that says nothing about how you will receive the data in your database client. MySQL converts text on the fly from the stored encoding to the connection encoding (and vice versa). When connecting to the database in your PHP code, you can choose which encoding you prefer to receive your data in. Use $mysqli->set_charset('utf8') to retrieve your data in UTF-8.