Querying Existing Query Results

The Query Results Data Source (QRDS) lets you run queries against results from your other Data Sources. Use it to join data from multiple databases or perform post-processing. Redash uses an in-memory SQLite database to make this possible. As a result, queries against large result sets may fail if Redash runs out of memory.

The QRDS doesn’t work with results from queries that use parameters. If you try it you’ll see Error running query: Failed loading results from query id xxxx. Remove the parameters from query_xxxx to fix the error.

Setup

You can enable Query Results under the Data Source tab of the settings menu. Setup is easy: just provide a name for the source.

This is the name that will appear in the source dropdown on the left of the query editor. The data source is called Query Results in the below screenshot.

Most organizations only require one Query Results data source.

Querying

The QRDS accepts SQLite query syntax:

SELECT
	a.name,
	b.count
FROM query_123 AS a
JOIN query_456 AS b
  		ON a.id = b.id

Your other queries are like “tables” to the QRDS. Each one is aliased as query_ followed by its query_id which you can see in the URL bar of your browser from the query editor. For example, a query at /queries/49588 has the alias query_49588.

The query alias like query_49588 must appear on the same line as its associated FROM or JOIN keyword.

Cached Query Results

When you query the Query Results Data Source, Redash executes the underlying queries first. This guarantees recent results in case you schedule a QRDS query. You can speed up QRDS queries by using cached_query_ for your query aliases instead of query_. This tells Redash to use the cached results from the most recent execution of a given query. This improves performance by using older data. You can mix both syntaxes in the same query too:

SELECT
	a.name,
	b.count
FROM cached_query_123 AS a
JOIN query_456 AS b
  		ON a.id = b.id

Query Results Permissions

Access to the Query Results Data Source is governed by the groups it’s associated with like any other Data Source. But Redash will also check if a user has permission to execute queries on the Data Sources the original queries use.

As an example, a user with access to the QRDS cannot execute SELECT * FROM query_123 if query 123 uses a data source to which that user does not have access. They will see the most recently cached QRDS query result from the query screen in Redash. But they will not be able to execute the query again.

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