[HIVE-7631] Add support for NOT operator in column regex

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 0.12.0
• Assignee: Unassigned
• Reporter: Mariano Dominguez
• Created: 06/Aug/14 17:34
• Updated: 10/Apr/20 15:03

Description

Given the following table:
0: jdbc:hive2://localhost:10000/default> DESCRIBE regex_column_tb;
-----------------------------------------------------------------

col_name

data_type

comment

-----------------------------------------------------------------

stage_c1	int	None
stage_c2	int	None
c1	int	None
c2	int	None

-----------------------------------------------------------------

A simple regex can be used to select certain columns:
0: jdbc:hive2://localhost:10000/default> SELECT `stage_.*` FROM regex_column_tb;
--------------------+

stage_c1

stage_c2

--------------------+
--------------------+

The regex “(?!stage_).*” using the NOT operator is a valid Java regex, but it does not seem to be supported in Hive:
0: jdbc:hive2://localhost:10000/default> SELECT `(?!stage_).*` FROM regex_column_tb;
Error: Error while compiling statement: FAILED: ParseException line 1:17 mismatched input ')' expecting FROM near 'stage_' in from clause (state=42000,code=40000)

The following regex is supported (HIVE-420), but it is not as intuitive:
0: jdbc:hive2://localhost:10000/default> SELECT `(stage_.*)?.` FROM regex_column_tb;
--------+

c1

c2

--------+
--------+

Issue Links

• is related to: HIVE-420 Support regular expressions for column in select clause
• is superceded by: HIVE-23176 Remove SELECT REGEX Column Feature