How should this judgment statement be written?

The if(isset($_POST['num'])) written before is now added with a condition and written like this if(isset(($_POST['num'])||($_GET['page'] )) But I get an error when I write it like this. How should I change it? ( ! ) Fatal error: Cannot use isset() on the result of an expression (you can use "null !== expression" instead) in D :wampwwwqq.php on line 76

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The if(isset($_POST['num'])) written before is now added with a condition and written like this if(isset(($_POST['num'])||($_GET['page'] )) But this is an error. How should I change it? ( ! ) Fatal error: Cannot use isset() on the result of an expression (you can use "null !== expression" instead) in D :wampwwwqq.php on line 76

isset can only be variables, not expressions.
can be changed to:

<code>if (isset($_POST['num']) || isset($_GET['page'])) {
    // TODO
}</code>