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mysql有没有一个算法生成一个特定id,该

发布时间: 2012-09-25 09:55:59 作者: rapoo

mysql有没有一个算法生成一个特定id
随机生成id

[解决办法]
没什么好办法,一种常见方法是,利用RAND随机函数生成一个,然后检查一下是否已经存在,如是存在则继续随机,直至找到一个不存在的。
[解决办法]
mysql> select cast(rand()*100 as SIGNED );
+-----------------------------+
| cast(rand()*100 as SIGNED ) |
+-----------------------------+
| 44 |
+-----------------------------+
1 row in set (0.01 sec)

mysql> select cast(rand()*100 as SIGNED );
+-----------------------------+
| cast(rand()*100 as SIGNED ) |
+-----------------------------+
| 27 |
+-----------------------------+
1 row in set (0.00 sec)

mysql> select cast(rand()*100 as SIGNED );
+-----------------------------+
| cast(rand()*100 as SIGNED ) |
+-----------------------------+
| 1 |
+-----------------------------+
1 row in set (0.00 sec)

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