Hexadecimal Literals SELECT _latin1 X’4D7953514C’; SELECT _utf8 0x4D7953514C COLLATE utf8_danish_ci; The examples use  X’ val ’  notation, but  0x val  notation permits introducers as well. For information about introducers, see Section 10.3.8, “Character Set Introducers” . In numeric contexts, MySQL treats a hexadecimal literal like a  BIGINT UNSIGNED  (64-bit unsigned integer). To ensure numeric treatment of a hexadecimal literal, use it in numeric context. Ways to do this include adding 0 or using  CAST(... AS UNSIGNED) . For example, a hexadecimal literal assigned to a user-defined variable is a binary string by default. To assign the value as a number, use it in numeric context: An empty hexadecimal value ( X’’ ) evaluates to a zero-length binary string. Converted to a number, it produces 0: The  X’ val ’  notation is based on standard SQL. The  0x  notation is based on ODBC, for which hexadecimal strings are often used to supply values for  BLOB  columns. To convert a string or a number to a string in hexadecimal format, use the  HEX()  function: For hexadecimal literals, bit operations are considered numeric context, but bit operations permit numeric or binary string arguments in MySQL 8.0 and higher. To explicitly specify binary string context for hexadecimal literals, use a  _binary  introducer for at least one of the arguments: mysql>  SET @v1 = X’000D’ | X’0BC0’; mysql>  SET @v2 = _binary X’000D’ | X’0BC0’; 1866 mysql>  SET @v1 = X’41’; mysql>  SET @v2 = X’41’+0; mysql>  SET @v3 = CAST(X’41’ AS UNSIGNED); mysql>  SELECT @v1, @v2, @v3; +------+------+------+ | @v1 | @v2 | @v3 | +------+------+------+ | A | 65 | 65 | +------+------+------+ +--------------+-------------+ | CHARSET(X’’) | LENGTH(X’’) | +--------------+-------------+ | binary | 0 | +--------------+-------------+ mysql>  SELECT CHARSET(X’’), LENGTH(X’’); mysql>  SELECT X’’+0; +-------+ | X’’+0 | +-------+ | 0 | +-------+ mysql>  SELECT HEX(’cat’); +------------+ | HEX(’cat’) | +------------+ | 636174 | +------------+ mysql>  SELECT X’636174’; +-----------+ | X’636174’ | +-----------+ | cat | +-----------+