mysql crc32函数

crc32() 索引url时使用
+-----------------------------------------+
| id | url                  | crc          |
+-----------------------------------------+
| 1  | http://www.mysql.com |  1560514994  |
+------------------------------------------+


select crc32('http://www.mysql.com');


+-------------------------------+
| crc32('http://www.mysql.com') |
+-------------------------------+
|                    1560514994 |
+-------------------------------+