[SPARK-28298] Fully support char and varchar types

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Won't Fix
• Affects Version/s: 3.0.0
• Component/s: SQL
• Assignee: Unassigned
• Reporter: Zhu, Lipeng
• Created: 08/Jul/19 10:17
• Updated: 29/Dec/19 06:30
• Resolved: 12/Sep/19 23:41

Description

Execute below SQL in Spark, the result is "abcdef".   But the result of other DBMS is "abc"(I think this is more sensible).

select cast("abcdef" as char(3));

And then I checked the source code, seems char/varchar only be used in DDL parse.

/**
 * Hive char type. Similar to other HiveStringType's, these datatypes should only used for
 * parsing, and should NOT be used anywhere else. Any instance of these data types should be
 * replaced by a [[StringType]] before analysis.
 */
case class CharType(length: Int) extends HiveStringType {
  override def simpleString: String = s"char($length)"
}

/**
 * Hive varchar type. Similar to other HiveStringType's, these datatypes should only used for
 * parsing, and should NOT be used anywhere else. Any instance of these data types should be
 * replaced by a [[StringType]] before analysis.
 */
case class VarcharType(length: Int) extends HiveStringType {
  override def simpleString: String = s"varchar($length)"
}

Is this behavior expected?