[SPARK-26215] define reserved keywords after SQL standard

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.4.0
• Fix Version/s: 3.0.0
• Component/s: SQL
• Target Version/s: 3.0.0
• Assignee: Takeshi Yamamuro
• Reporter: Wenchen Fan
• Created: 29/Nov/18 11:03
• Updated: 05/Feb/20 06:16
• Resolved: 22/Feb/19 23:41

Description

There are 2 kinds of SQL keywords: reserved and non-reserved. Reserved keywords can't be used as identifiers.

In Spark SQL, we are too tolerant about non-reserved keywors. A lot of keywords are non-reserved and sometimes it cause ambiguity (IIRC we hit a problem when improving the INTERVAL syntax).

I think it will be better to just follow other databases or SQL standard to define reserved keywords, so that we don't need to think very hard about how to avoid ambiguity.

For reference: https://www.postgresql.org/docs/8.1/sql-keywords-appendix.html

Issue Links

• contains: SPARK-22553 Drop FROM in nonReserved
• is related to: SPARK-20964 Make some keywords reserved along with the ANSI/SQL standard
• is related to: SPARK-27060 DDL Commands are accepting Keywords like create, drop as tableName
• relates to: SPARK-26905 Revisit reserved/non-reserved keywords based on the ANSI SQL standard
• relates to: SPARK-20964 Make some keywords reserved along with the ANSI/SQL standard
• links to: [Github] Pull Request #23259 (maropu)
• links to: [Github] Pull Request #23259 (maropu)
• links to: GitHub Pull Request #23259
• links to: GitHub Pull Request #23897