[HIVE-25028] Hive: Select query with IS operator producing unexpected result

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Component/s: Parser
• Labels: pull-request-available
• Assignee: Soumyakanti Das
• Reporter: Manthan B Y
• Created: 19/Apr/21 12:29
• Updated: 21/Apr/21 14:21
• Resolved: 21/Apr/21 14:21

Description

Hive: Select query with IS operator is producing unexpected result.

The following was executed on postgres:

sqlancer=# create table if not exists emp(name text, age int);
CREATE TABLE
sqlancer=# insert into emp values ('a', 5), ('b', 15), ('c', 12);
INSERT 0 3
sqlancer=# select emp.age from emp where emp.age > 10;
 age
-----
  15
  12
(2 rows)sqlancer=# select emp.age > 10 is true from emp;
 ?column?
----------
 f
 t
 t
(3 rows)

This is happening because IS operator has higher precedence than comparison operators in Hive. In most other databases, comparison operator has higher precedence. The grammar needs to be changed to fix the precedence.

Issue Links

• links to: GitHub Pull Request #2190