MySQL DB data type field to store hash for comparision?

[Ahnungsloser]

$hasher = new ImageHash();
$hash = $hasher->hash('test.jpg');

... returns hash in HEX-Format like "3c3e0e1a3a1e1e1e".
tried to convert it: $hash->toBin(), but I'll get fatal error.

Do I have to store the returend hash in the format like in the example (Image 1 hash: 3c3e0e1a3a1e1e1e ), or do I have to convert it to binary format (0011110000111110000011100001101000111010000111100001111000011110)?

Which data type to use for the column to store it in a mysql database for comparision ... varchar(), int()

If I save the hashes in HEX ("3c3e0e1a3a1e1e1e") and try to get the hamming distance, results seems not to be correct.

Results from DB ...
SELECT images.*, BIT_COUNT(hash ^ :hash) as hamming_distance
FROM images
HAVING hamming_distance < 5

... are significantly different from ...
$hasher = new ImageHash(new DifferenceHash());
$distance = $hasher->distance($hash3, $hash4);

[VincentChalnot]

You need to store the hash as an unsigned bigint on MySQL side. (Unfortunately MySQL can't do bitwise operations on varbinary types)
Be careful to keep the number as a string on PHP side because PHP doesn't support unsigned integers and the hash can "overflow" and be cast to float when using the Hash::toInt() method.