Question

Does a char occupy 1 byte in a database?

EDIT:
If I define a column as varchar(1), will it reserve 1 or 2 bytes for me?

Answer 1

Char(k) takes k-bytes no matter what the value is,
varchar(k) n+1 bytes, where n = number of chars in the value, but max k+1 bytes

Value       CHAR(4)    Storage Required     VARCHAR(4)      Storage Required
''          '    '     4 bytes              ''              1 byte
'ab'        'ab  '     4 bytes              'ab'            3 bytes
'abcd'      'abcd'     4 bytes              'abcd'          5 bytes
'abcdefgh'  'abcd'     4 bytes              'abcd'          5 bytes

http://dev.mysql.com/doc/refman/5.1/en/char.html