[SPARK-14878] Support Trim characters in the string trim function

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.0
• Fix Version/s: 2.3.0
• Component/s: SQL
• Target Version/s: 2.3.0
• Assignee: kevin yu
• Reporter: kevin yu
• Created: 23/Apr/16 22:18
• Updated: 07/Feb/18 07:36
• Resolved: 18/Sep/17 20:11

Description

The current Spark SQL does not support the trim characters in the string trim function, which is part of ANSI SQL2003’s standard. For example, IBM DB2 fully supports it as shown in the https://www.ibm.com/support/knowledgecenter/SS6NHC/com.ibm.swg.im.dashdb.sql.ref.doc/doc/r0023198.html. We propose to implement it in this JIRA..
The ANSI SQL2003's trim Syntax:

SQL
<trim function> ::= TRIM <left paren> <trim operands> <right paren>
<trim operands> ::= [ [ <trim specification> ] [ <trim character> ] FROM ] <trim source>
<trim source> ::= <character value expression>
<trim specification> ::=
  LEADING
| TRAILING
| BOTH
<trim character> ::= <character value expression>    

Issue Links

• links to: [Github] Pull Request #12646 (kevinyu98)
• links to: [Github] Pull Request #19302 (kevinyu98)