TimeBoundary queries

TimeBoundary - 图1info

Apache Druid supports two query languages: Druid SQL and native queries. This document describes a query type that is only available in the native language.

Time boundary queries return the earliest and latest data points of a data set. The grammar is:

  1. {
  2.     "queryType" : "timeBoundary",
  3.     "dataSource": "sample_datasource",
  4.     "bound"     : < "maxTime" | "minTime" > # optional, defaults to returning both timestamps if not set
  5.     "filter"    : { "type": "and", "fields": [<filter>, <filter>, ...] } # optional
  6. }

There are 3 main parts to a time boundary query:

propertydescriptionrequired?
queryTypeThis String should always be “timeBoundary”; this is the first thing Apache Druid looks at to figure out how to interpret the queryyes
dataSourceA String or Object defining the data source to query, very similar to a table in a relational database. See DataSource for more information.yes
boundOptional, set to maxTime or minTime to return only the latest or earliest timestamp. Default to returning both if not setno
filterSee Filtersno
contextSee Contextno

The format of the result is:

  1. [ {
  2.   "timestamp" : "2013-05-09T18:24:00.000Z",
  3.   "result" : {
  4.     "minTime" : "2013-05-09T18:24:00.000Z",
  5.     "maxTime" : "2013-05-09T18:37:00.000Z"
  6.   }
  7. } ]