lightdb内置函数可生成
```
[zjh@hs-10-20-30-193 data]$ ltsql -p9999
ltsql (13.3-22.2)
Type "help" for help.
zjh@postgres=# select round(random() * 10000000,2);
round
Original: https://www.cnblogs.com/zhjh256/p/16388603.html
Author: zhjh256
Title: lightdb生成随机数