The Binary Character Set The  binary  character set is the character set for binary strings, which are sequences of bytes. The binary  character set has one collation, also named  binary . Comparison and sorting are based on numeric byte values, rather than on numeric character code values (which for multibyte characters differ from numeric byte values). For information about the differences between the  binary  collation of the binary  character set and the  _bin  collations of nonbinary character sets, see Section 10.8.5, “The binary Collation Compared to _bin Collations” . For the  binary  character set, the concepts of lettercase and accent equivalence do not apply: •For single-byte characters stored as binary strings, character and byte boundaries are the same, so lettercase and accent differences are significant in comparisons. That is, the  binary  collation is case- sensitive and accent-sensitive. •For multibyte characters stored as binary strings, character and byte boundaries differ. Character boundaries are lost, so comparisons that depend on them are not meaningful. To perform lettercase conversion of a binary string, first convert it to a nonbinary string using a character set appropriate for the data stored in the string: BINARY  expr CAST( expr  AS BINARY) CONVERT( expr  USING BINARY) _binary ’a’ 1986 Note Within the  mysql  client, binary strings display using hexadecimal notation, depending on the value of the  --binary-as-hex . For more information about that option, see Section 4.5.1, “mysql — The MySQL Command-Line Client” . For more information about introducers, see Section 10.3.8, “Character Set Introducers” . The  _binary  introducer is permitted for hexadecimal literals and bit-value literals as well, but unnecessary; such literals are binary strings by default. If a value is a character string literal, the  _binary  introducer may be used to designate it as a binary string. For example: To convert a string expression to a binary string, these constructs are equivalent: mysql>  SET @str = BINARY ’New York’; mysql>  SELECT LOWER(@str), LOWER(CONVERT(@str USING utf8mb4)); +-------------+------------------------------------+ | LOWER(@str) | LOWER(CONVERT(@str USING utf8mb4)) | +-------------+------------------------------------+ | New York | new york | +-------------+------------------------------------+ +----------------+------------------+ | CHARSET(’abc’) | COLLATION(’abc’) | +----------------+------------------+ | binary | binary | +----------------+------------------+ +---------------+------------+ | ’abc’ = ’ABC’ | ’a’ = ’ä’ +---------------+------------+ | 0 | 0 | +---------------+------------+ mysql>  SELECT ’abc’ = ’ABC’, ’a’ = ’ä’; mysql>  SET NAMES ’binary’; mysql>  SELECT CHARSET(’abc’), COLLATION(’abc’);