[HIVE-783] Implement disjunctive JOINs

• Type: New Feature
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: Query Processor
• Assignee: Unassigned
• Reporter: Adam Kramer
• Created: 23/Aug/09 19:34
• Updated: 10/Jan/11 07:06

Description

Currently, Hive does not allow disjunctive joins. For example:

SELECT ...
FROM a
JOIN b ON (a.key1=b.key1 OR a.key1=b.key2)

...currently fails. The current workaround is to join on each, UNION ALL them, and then somehow figure out a way to remove any duplicates (wher b.key1=b.key2 and there's a corresponding a.key1)...but this involves many passes through the same data.

Issue Links

• relates to: HIVE-801 row-wise IN would be useful