[SPARK-4151] Add string operation function trim, ltrim, rtrim, length to support SparkSql (HiveQL)

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Duplicate
• Affects Version/s: 1.1.0
• Fix Version/s: 1.5.0
• Component/s: SQL
• Assignee: Unassigned
• Reporter: OopsOutOfMemory
• Created: 30/Oct/14 08:07
• Updated: 19/Jul/15 23:57
• Resolved: 19/Jul/15 23:57

Description

Add three string operation functions to support spark sql and hiveql.
eg:
sql("select trim(' a b ') from src ").collect() --> 'a b'
sql("select ltrim(' a b ') from src ").collect() --> 'a b '
sql("select rtrim(' a b ') from src ").collect() --> ' a b'
sql("select length('ab') from src ").collect() --> 2

And Rename the trait of stringOperations.scala.
I prefer to rename trait CaseConversionExpression to StringTransformationExpression, it is more make sence than before so that this trait can support more string transformation but not only caseconversion.

And also add a trait StringCalculationExpression that do string computation like length, indexof etc....

Issue Links

• is blocked by: SPARK-4867 UDF clean up
• links to: [Github] Pull Request #2998 (OopsOutOfMemory)