[TAJO-1514] Distinguish UNION and UNION ALL

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.11.0
• Assignee: Keuntae Park
• Reporter: Keuntae Park
• Created: 03/Apr/15 06:20
• Updated: 17/Jul/15 02:36
• Resolved: 17/Jul/15 01:38

Description

Currently, Tajo handles both UNION and UNION ALL as UNION ALL.
For UNION, however, result should not have duplicated rows.
It needs to handle them differently.