Appearance
日期表达式用法举例: 
| Relative range example | From | Until | 
|---|---|---|
| Last 5 minutes | now-5m | now | 
| So far today | now/d | now | 
| This week | now/w | now/w | 
| Last week | now-1w/w | now-1w/w | 
| So far this week | now/w | now | 
| Current month | now/M | now/M | 
| Last month | now-1M/M | now-1M/M | 
| This month to date | now/M | now | 
| So far this year | now/Y | now | 
| This year | now/Y | now/Y | 
| Last year | now-1y/y | now-1y/y | 
| The last 13 months | now-13M/M | now-1M/end | 
| From 00:00 on the day of last month to the end of last month | now-1M/d | now-1M/d | 
注:now是指cube的更新时间:
