[HIVE-15517] NOT (x <=> y) returns NULL if x or y is NULL

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.2.1, 2.0.0, 2.1.0
• Fix Version/s: 2.2.0
• Component/s: Hive, Operators, Query Processor, SQL
• Assignee: Pengcheng Xiong
• Reporter: Alexey Bedrintsev
• Created: 27/Dec/16 11:26
• Updated: 26/Jul/17 00:03
• Resolved: 01/Feb/17 21:28

Description

I created a table as following:

create table test(x string, y string);
insert into test values ('q', 'q'), ('q', 'w'), (NULL, 'q'), ('q', NULL), (NULL, NULL);

Then I try to compare values taking NULLs into account:

select *, x<=>y, not (x<=> y), (x <=> y) = false from test;
OK
q q true false false
q w false true true
q NULL false NULL true
NULL q false NULL true
NULL NULL true NULL false

I expected that 4th column will be the same as 5th one but actually got NULL as result of "not false" and "not true" expressions.

Hive 1.2.1000.2.5.0.0-1245
Subversion git://c66-slave-20176e25-3/grid/0/jenkins/workspace/HDP-parallel-centos6/SOURCES/hive -r da6c690d384d1666f5a5f450be5cbc54e2fe4bd6
Compiled by jenkins on Fri Aug 26 01:39:52 UTC 2016
From source with checksum c30648316a632f7a753f4359e5c8f4d6

Issue Links

• relates to: HIVE-16768 NOT operator returns NULL from result of <=>