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MySQL supports hexadecimal values. In numeric contexts, these act like integers (64-bit precision). In string contexts, these act like binary strings, where each pair of hex digits is converted to a character:
mysql> SELECT x'4D7953514C'; -> 'MySQL' mysql> SELECT 0xa+0; -> 10 mysql> SELECT 0x5061756c; -> 'Paul' |
In MySQL 4.1 (and in MySQL 4.0 when using the --new
option) the default
type of of a hexadecimal value is a string. If you want to ensure that
the value is treated as a number, you can use CAST(... AS UNSIGNED)
:
mysql> SELECT 0x41, CAST(0x41 AS UNSIGNED); -> 'A', 65 |
The 0x
syntax is based on ODBC. Hexadecimal strings are often used by
ODBC to supply values for BLOB
columns.
The x'hexstring'
syntax is new in 4.0 and is based on standard SQL.
Beginning with MySQL 4.0.1, you can convert a string or a number to a string
in hexadecimal format with the HEX()
function:
mysql> SELECT HEX('cat'); -> '636174' mysql> SELECT 0x636174; -> 'cat' |