[CALCITE-6254] Support table function calls in FROM clause without TABLE() wrapper

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 1.36.0
• Fix Version/s: 1.37.0
• Component/s: core
• Labels: parser pull-request-available
• Assignee: Unassigned
• Reporter: Barry Kelly
• Created: 08/Feb/24 09:27
• Updated: 06/May/24 22:19
• Resolved: 22/Feb/24 09:57

Description

Currently, when selecting from a table function, the function call needs to be wrapped in TABLE() like this:

    SELECT * FROM TABLE(table_func('args'));

Many dialects (SQL Server, PostgreSQL, BigQuery) do not require this:

    SELECT * FROM table_func('args');

The current Calcite grammar can be extended to permit this syntax without conflicting with other productions.

There is a close call with the dynamic columns feature used by Phoenix

    SELECT * FROM EventLog(lastGCTime TIME)

It can be disambiguated with 3 tokens of lookahead, seeing past the '(' and identifier to the presence of a type production. The table extension clause for dynamic columns requires at least one field, so the empty case of '()' is not ambiguous either.

Issue Links

• is duplicated by: CALCITE-1490 Allow table functions without explicit TABLE
• links to: GitHub Pull Request #3693