CRC32(expr) returns a cyclic redundancy check value and returns a 32-bit unsigned value. : CRC32 « Math Numeric Functions « MySQL Tutorial

1. MySQL Tutorial
2. Math Numeric Functions
3. CRC32

The result is NULL if the argument is NULL.

mysql> SELECT CRC32('java2s.com');
+---------------------+
| CRC32('java2s.com') |
+---------------------+
|            91442478 |
+---------------------+
1 row in set (0.00 sec)

mysql>
mysql>