Which MySQL collation exactly matches PHP's string comparison?

Question

Here is a MySQL query:

SELECT last_name FROM users ORDER BY last_name

We get all that data into PHP and then run:

$prior = NULL;
do {
    $current = array_shift($results);
    assert($current >= $prior);
    $prior = $current;
} while ($current !== NULL);

Currently this assertion fails for certain inputs. Is it possible to add a COLLATE clause to the MySQL query above to absolutely guarantee that PHP assertion?

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Stuff I tried:

• The above code, it doesn't work for certain non-ASCII inputs
• ORDER BY email COLLATE utf8_bin resulted in COLLATION 'utf8_bin' is not valid for CHARACTER SET 'latin1'
• Maybe this is a duplicate of What is the best collation to use for MySQL with PHP? but that seemed more subjective, I am seeking a specific answer to a specific problem

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Others notes:

• If it makes a difference, this column is latin1
• My PHP PDO wrapper library is https://github.com/fulldecent/thin-pdo

Answer 1

echo ('a' == 'A') ? 'a==A ' : 'a <> A ';
echo ('a' == 'á') ? 'a==á ' : 'a <> á ';

Both came back <>, so I deduce that PHP acts like latin1_bin (or the _bin of whatever charset you have).