[SPARK-2431] Refine StringComparison and related codes.

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.0.2, 1.1.0
• Component/s: SQL
• Assignee: Takuya Ueshin
• Reporter: Takuya Ueshin
• Created: 10/Jul/14 16:21
• Updated: 11/Jul/14 02:21
• Resolved: 11/Jul/14 02:21

Description

Refine StringComparison and related codes as follows:

• StringComparison could be similar to StringRegexExpression or CaseConversionExpression.
• Nullability of StringRegexExpression could depend on children's nullabilities.
• Add a case that the like condition includes no wildcard to LikeSimplification.