MySQL has column type of bit which returns binary zero (\0) or binary one (\1), which is not properly displayed - both of these chars aren't renderable and thus appear as empty column.
Properly display value of type bit (from MySQL)
Btw this PR isn't probably the best way of solving this issue, but it's the best I can do with my brief knowledge of adminer's internals. And it works for me ;)
It looks like a bug in PHP 5.3: https://bugs.php.net/bug.php?id=63244
Seems to be fine in PHP 5.4 as it is right now in master.
There's also bit(2) and more so \1 is not the only possible value. With bit(6), it's possible to get \x30 which is 0.
Yep, this seemed like a great idea at first but then I realised how stupid it is.