MySQL Reference Manual for version 4.0.18.

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10.1.3 Hexadecimal Values

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'



This document was generated by rdg (Feb 25 2004) using texi2html