PHP+Mysql : update not work if use '&' contain WHERE - php

Question

This code not work :
UPDATE `test` SET `done`='1' WHERE `name`='x_&_y'
But this is work :
UPDATE `test` SET `done`='1' WHERE `name`='x_y'
Both of code return 1 value but first code not work and table not updated !
PHP code :
$value = 'x_&_y'; // send by $_GET['value']
$value = htmlspecialchars(trim($value),ENT_QUOTES,'UTF-8');
UPDATE `league` SET `leagueUpdateDone`='1' WHERE `leagueCountry`='$value';

Answer 1

The problem is you're running your query wrong. Never, ever use htmlspecialchars on input if you're trying to match things. & is a reserved character in HTML, it will be mangled.
Your final query looks like:
'x_&_y'
Instead use prepared statements with placeholder values, like this:
$stmt = $db->prepare('UPDATE `league` SET `leagueUpdateDone`='1' WHERE `leagueCountry`=?');
Then bind values against that. The procedure varies in implementation based on your use of mysqli or PDO.
Note: htmlspecialchars is only used for displaying HTML. Keep the content in your database as neutral as possible, never pre-escaped. You want to treat everything in your database as raw, escaping it for the context it's used in, be that JSON, HTML, email or otherwise, on a case-by-case basis. If you presume it's HTML that can make life very ugly if you need to undo that and re-do it for JSON, for example.
I don't know where you learned that htmlspecialchars technique, but it's highly probable this is cargo cult programming where incantations are used without their purpose being fully understood. This is a common problem with a lot of YouTube tutorial-type training where they drown you in code but offer very little in the way of theoretical foundation or practical explanations.
I'm trying not to be too hard on you here, you're just trying to learn, but it's important to understand the code you're using instead of just using it because someone told you to. Try to dig a little deeper, look up the documentation on the methods you're using. PHP has a fantastic manual with a comments section full of people helping to clarify any misunderstandings.