Hexadecimal Literals recognized. For information about fractional seconds support in MySQL, see Section 11.2.6, “Fractional Seconds in Time Values” . For  TIME  values specified as strings that include a time part delimiter, it is unnecessary to specify two digits for hours, minutes, or seconds values that are less than  10 .  ’8:3:2’  is the same as  ’08:03:02’ . Hexadecimal literal values are written using  X’ val ’  or  0x val  notation, where  val  contains hexadecimal digits ( 0..9 ,  A..F ). Lettercase of the digits and of any leading  X  does not matter. A leading  0x  is case- sensitive and cannot be written as  0X . Legal hexadecimal literals: Illegal hexadecimal literals: X’01AF’ X’01af’ x’01AF’ x’01af’ 0x01AF 0x01af X’0G’ (G is not a hexadecimal digit) 0X01AF (0X must be written as 0x) 9.1.4 Hexadecimal Literals Values written using  X’ val ’  notation must contain an even number of digits or a syntax error occurs. To correct the problem, pad the value with a leading zero: Values written using  0x val  notation that contain an odd number of digits are treated as having an extra leading  0 . For example,  0xaaa  is interpreted as  0x0aaa . By default, a hexadecimal literal is a binary string, where each pair of hexadecimal digits represents a character: A hexadecimal literal may have an optional character set introducer and  COLLATE  clause, to designate it as a string that uses a particular character set and collation: Examples: 1865 [_ charset_name ] X’ val ’ [COLLATE  collation_name ] mysql>  SELECT X’4D7953514C’, CHARSET(X’4D7953514C’); +---------------+------------------------+ | X’4D7953514C’ | CHARSET(X’4D7953514C’) | +---------------+------------------------+ | MySQL | binary | +---------------+------------------------+ mysql>  SELECT 0x5461626c65, CHARSET(0x5461626c65); +--------------+-----------------------+ | 0x5461626c65 | CHARSET(0x5461626c65) | +--------------+-----------------------+ | Table | binary | +--------------+-----------------------+ mysql>  SET @s = X’FFF’; ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ’X’FFF’’ mysql>  SET @s = X’0FFF’; Query OK, 0 rows affected (0.00 sec)