[CALCITE-6337] Distinguish naked measure support between inside and outside aggregation

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.37.0
• Component/s: core
• Labels: pull-request-available
• Assignee: Unassigned
• Reporter: Barry Kelly
• Created: 20/Mar/24 13:56
• Updated: 06/May/24 22:19
• Resolved: 24/Mar/24 18:43

Description

Measure type and AGGREGATE function (CALCITE-5105) introduced a configuration flag for naked measures.

Naked measures are measure-typed columns that are referenced outside an AGGREGATE() function call.

At Looker, we're trying to support a specific semantic using measure-typed columns:

• selecting from a naked measure-typed column outside an aggregating query evaluates to NULL
  This permits basic introspection of the schema like `SELECT * FROM foo LIMIT 1`
  For this, we need naked measures outside a grouping context.
• selecting from a naked measure-typed column inside an aggregating query is an error
  We want all expressions in a grouping query to either be part of the grouping key or to have
  an aggregation function applied. For this, we don't want naked measures inside a grouping context.

This change proposes:

• nakedMeasuresOutsideAggregatingQuery - boolean flag permitting measure references outside aggregating query
• nakedMeasuresInsideAggregatingQuery - boolean flag permitting measure references inside aggregating query
• deprecating nakedMeasures flag, which is now implemented by setting both of the above to the same value

Issue Links

• links to: GitHub Pull Request #3738