Appboard/2.4/builder/data sources/sub-query

The Sub-Query data adapter is used to perform queries and transformation against other data source entities. This does not appear in the adapter type chooser when adding a data source, instead select an existing data source and click the Create Sub-Query button.

Typical uses for the Sub-Query data adapter are when raw information needs to be summarized or transformed in a way to support a particular visualization:

• Grouping: group by one or more columns and calculate counts, or max/min values.
• Pivoting: transform row-oriented data into column-oriented data
• Sub-select: select a sub-set of columns
• Filtering: general operator and value based filtering to reduce the data set.
• Sorting: sort by one or more columns
• Limit Row Count: reduce the data set - returns the top most rows within the limit.

Data Collections also provide some overlapping functionality, specifically the ability to sort, limit rows, and filtering.

Sub-Query example configuration.