[SPARK-49653] Support single joins for full scalar subquery decorrelation

• Type: New Feature
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 4.0.0
• Fix Version/s: 4.0.0
• Component/s: SQL
• Labels: pull-request-available
• Assignee: Andrey Gubichev
• Reporter: Andrey Gubichev
• Created: 15/Sep/24 22:10
• Updated: 23/Sep/24 02:59
• Resolved: 23/Sep/24 02:59

Description

We should introduce Single join operator to fully support scalar subqueries.

The operator would ensure that the scalar subquery returns at most 1 row and issue a runtime error otherwise.

Design doc: https://docs.google.com/document/d/1NTsvtBTB9XvvyRvH62QzWIZuw4hXktALUG1fBP7ha1Q/edit

Issue Links

• links to: GitHub Pull Request #48145