SQL

1、时间对齐模式下的排序(asc、desc 升降序)

select * from root.sg.TAS894D order by time desc

select * from root.ftkj.lg01.zl01 order by time desc

select * from root.sg.USRN510 order by time desc

2、查询最新一条数据

select last_value(*) from root.realdata.`DL01.5`

SELECT last_value(a1) FROM root.sg.USRN510

3、按照 time字段的降序排列来选取最新的一条数据。

select * from root.realdata.```DL01.8 ORDER BY time DESC LIMIT 1

-- 最新一条数据 如果数据路径是一个层次化的序列名称
SELECT * 
FROM root.group.device.sensor
WHERE time = NOW - 1d -- 获取最近一天内的最新数据点
ORDER BY time DESC 
LIMIT 1;

4、删除多列数据

delete from root.ln.wf02.wt02.* where time <= 2017-11-01T16:26:00;

https://www.bookstack.cn/read/iotdb-1.2-zh/5457e5e716ebdd28.md#%E5%88%A0%E9%99%A4%E6%95%B0%E6%8D%AE

5、删除时间序列

delete timeseries root.sg.TAS894D.*
delete timeseries root.ln.wf01.wt01.status
delete timeseries root.ln.wf01.wt01.temperature, root.ln.wf02.wt02.hardware
delete timeseries root.ln.wf02.*
drop timeseries root.ln.wf02.*