influxdb time series database new/delete continuous query, data insertion

influxdb time series database new/delete continuous query

Dbs:{
    
    
      host: "192.168.0.1",
      port: 8086,
      database: "mydb",
      username: "root",
      password: "root"
    }

1. New continuous query

const Influx = require('influx');
const influx = new Influx.InfluxDB(Dbs)
await influx.createContinuousQuery(<连续查询名称>, <sql>, <时序数据库名>, <执行间隔>)
//连续查询名称 ——> dataanalysis
//sql ——> select count(FYJYL) as nsywzerototal INTO dataanalysis.autogen.dataanalysis FROM mydb.autogen.processdata  where FYJYL = 0 group by time(1d),SBXLH fill(0)
//时序数据库名 ——> mydb
//执行间隔 ——> RESAMPLE EVERY 4h

2. Delete continuous query

 const influx = new Influx.InfluxDB(Dbs)
 await influx.dropContinuousQuery(<连续查询名称>, <时序数据库名>)

3. Query

const influx = new Influx.InfluxDB(Dbs)
await influx.query(`select ...`).then(result=>{
    
    })

4. Precautions for continuous query

(1) When the content field of the query cannot be inserted into the table in one continuous query, multiple continuous queries can be created, but the repeated fields cannot be included, otherwise the content of the repeated fields will be overwritten
; When the key fields are the same, its content will be overwritten by the latest data, that is, there is only one piece of data for the same key at the same time.

5. SQL direct execution

Official website portal: https://docs.influxdata.com/influxdb/v1.7/query_language/continuous_queries/
involves INTO knowledge points

SELECT_clause INTO <插入的表> FROM_clause [WHERE_clause] [GROUP_BY_clause]
#select count(FYJYL) as nsywzerototal INTO dataanalysis.autogen.dataanalysis FROM mydb.autogen.processdata  where FYJYL = 0 group by time(1d),SBXLH fill(0)

New continuous query

CREATE CONTINUOUS QUERY <连续查询名称> ON <库名>
RESAMPLE EVERY <执行时间间隔> FOR 执行时间范围
BEGIN
  <cq_query>
END

For example, RESAMPLE EVERY 30m FOR 60m ==> calculates the data within 60 minutes every 30 minutes

6. Visually create a new continuous query

insert image description here

7. Continuous query execution order problem

The order in which continuous queries are created refers to the order in which continuous queries are executed. Continuous queries created first are executed first; time-series databases continue to insert data, so there may be errors between statistical data and actual data (it is inevitable to use continuous queries).

8. Data insertion

insert table without will be created automatically

influx.writePoints([{
	 measurement: 'table_name',//表名
	 tags:{code:4401},
	 fields: { time:'2022-12-01 14:00:00', value:100.02 } //字段
}])

await influx.query(`select ...`).then(result=>{
	console.log(result) // [{time:'2022-12-01 14:00:00',value:100.02,code:4401}]
})

Reference: https://node-influx.github.io/class/src/index.js~InfluxDB.html