[HIVE-2901] Hive union with NULL constant and string in same column returns all null

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Fix Version/s: 0.9.0
• Hadoop Flags: Reviewed
• Assignee: Navis Ryu
• Reporter: Kevin Wilfong
• Created: 24/Mar/12 01:53
• Updated: 14/May/13 08:07
• Resolved: 06/Apr/12 06:08

Description

select x from (select value as x from src union all select NULL as x from src)a;

This query produces all nulls, where value is a string column.

Notably,
select x from (select key as x from src union all select NULL as x from src)a;
where key is a string, but can be cast to a double, the query returns correct results.

Issue Links

• duplicates: HIVE-747 void type (null column) cannot be UNIONed with other type