[CALCITE-3220] In JDBC adapter, when generating SQL for Hive, transform TRIM function to TRIM, LTRIM or RTRIM

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 1.19.0
• Fix Version/s: 1.21.0
• Component/s: core
• Labels: pull-request-available
• Assignee: Julian Hyde
• Reporter: Jacky Woo
• Created: 31/Jul/19 07:52
• Updated: 10/Sep/19 21:37
• Resolved: 23/Aug/19 05:41

Description

Let's assume sql = SELECT TRIM(' str ')

When we use HiveSqlDialect and transform "sql", we expect SELECT TRIM(' str ')，but get SELECT TRIM(BOTH ' ' FROM ' str ') which is incorrect  sql format in hive.

So maybe HiveSqlDialect behavior should be changed when transform function trim:

1. SELECT TRIM(' str ')  =>  SELECT TRIM(' str ') 
2. SELECT TRIM(BOTH ' ' from ' str ') => SELECT TRIM(' str ')
3. SELECT TRIM(LEADING ' ' from ' str ') => SELECT LTRIM(' str ')
4. SELECT TRIM(TRAILING ' ' from ' str ')=>  SELECT RTRIM(' str ') 

Issue Links

• links to: GitHub Pull Request #1342
• links to: PR#1342