suneet-s commented on a change in pull request #9704: Refresh query docs. URL: https://github.com/apache/druid/pull/9704#discussion_r409097131
########## File path: docs/querying/datasource.md ########## @@ -22,43 +22,317 @@ title: "Datasources" ~ under the License. --> +Datasources in Apache Druid are things that you can query. The most common kind of datasource is a table datasource, +and in many contexts the word "datasource" implicitly refers to table datasources. This is especially true +[during data ingestion](../ingestion/index.html), where ingestion is always creating or writing into a table +datasource. But at query time, there are many other types of datasources available. -A data source is the Apache Druid equivalent of a database table. However, a query can also masquerade as a data source, providing subquery-like functionality. Query data sources are currently supported only by [GroupBy](../querying/groupbyquery.md) queries. +In the [Druid SQL](sql.html) language, datasources are provided in the [`FROM` clause](sql.html#from). Review comment: oops - I thought the "JOIN" statement was on the same level as FROM, WHERE, etc. 🤦 Maybe a better example is subqueries that are part of a filter ``` SELECT table.key, table.metric from table where table.key = (select ANY_VALUE(lookyloo.k) from lookup.lookyloo where lookyloo.v='FILTER') ``` ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@druid.apache.org For additional commands, e-mail: commits-h...@druid.apache.org
