mysql> SELECT RAND( ), RAND( ), RAND( );
+------------------+-----------------+------------------+
| RAND( ) | RAND( ) | RAND( ) |
+------------------+-----------------+------------------+
| 0.45464584925645 | 0.1824410643265 | 0.54826780459682 |
+------------------+-----------------+------------------+
可根据自己需求 RAND() * i [i值变动].