Problems with sql query in php - php

Question

so, I'm using one query to get the profile photo, i'm using the follow query:
$sql = "SELECT photo FROM users WHERE login = '$username'";
I already tried many ways to do, with and without the inverted commas.
$sql = "SELECT `photo` FROM `users` WHERE `login` = '$username'";
Next code is like:
$result = mysqli_query($link, $sql);
echo "<script>console.log('photo: ".$sql."');</script>";
When I check the console i see this error:
Uncaught SyntaxError: missing ) after argument list
When I do the query with just "select photo from users" it returns a value.
On another page I use the same code to get the permissions and it returns a value that I want
$sql = "SELECT permission FROM users where login = '$username'";
$result = mysqli_query($link, $sql);
if ($result->num_rows > 0) {
while ($row = mysqli_fetch_array($result)) {
$save = $row[0];
}
}
Permission Column is int;
Photo Column is varchar;

Answer 1

Since the query contains single quotes, you can't use single quotes around the argument to console.log(), because the quote in the query will terminate the JavaScript string.
Put double quotes around the JS string.
echo "<script>console.log(\"photo: ".$sql."\");</script>";

Answer 2

Your javascript console is wrapped in ' quotes, and your '$username' value is also using these single quotes so this is causing a problem.
Therefore; if you want to export this SQL string to your console, you need to escape these single quotes or to use alternative quotes in your javascript.
This issue is better resolved by Barmar's Answer.
BUT:
Best Practise; you should NOT be outputting SQL strings to your browser at all. This is a potentially severe security hole. Instead (especailly if your SQL server is 'localhost') you should be outputting your SQL data to your PHP error logs:
$result = mysqli_query($link, $sql);
//echo "<script>console.log('photo: ".$sql."');</script>";
error_log("Query Output: ".print_r($sql,true));
Then in your IDE or secured server connection (SFTP etc.) then you can access the PHP Error Logs and view the SQL more safely.
See also: Where does PHP store the error log? (php5, apache, fastcgi, cpanel)