If you are using influxdb, one usecase could be, copy the data from a measurement ("table") to another.
This can be done with this statement:
select * into testtable2 from testtable1
By the way: the CLI is opened with
/usr/bin/influx -unsafeSsl -ssl -database telegraf(if your database is named telegraf)
In my case (zigbee / mqtt / telegraf) the layout of mqtt_consumer measurement was like this:
> show tag keys from mqtt_consumerBut after copying this to a testtable, the tags where gone and everything was a field.
> show field keys from mqtt_consumer
This is not a big problem - you can work with that data without a problem. BUT if you want to copy it back or merge it to the original table, you will get a table with the additional columns host_1 and topic_1.
This is because for influx you already had a column host. So it added a column field host_1.
If a query in this new table (with host + host_1) spans over a time where both of this columns are in, you only select the data, with the entry host. If the time spans only entries with host_1, it is shown as host and you get your data. Really a unpredictable way to get data.
What is the solution? Easy:
select * into table1 from mqtt_consumer group by host,topicThe "group by" does not group anything. It just tells influx: host & topic are tags and not fields. Please do not transform them...