[FLINK-6124] support max/min aggregations for string type

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.3.0
• Component/s: Table SQL / API
• Assignee: Zhenghua Gao
• Reporter: Zhenghua Gao
• Created: 20/Mar/17 09:30
• Updated: 03/Apr/17 16:26
• Resolved: 21/Mar/17 11:24

Description

Recently when I port some query to Flink SQL, I found currently min/max aggregations on string type is not supported and should be added.
When min/max aggregations are used on string column, return min/max value by lexicographically order.

Issue Links

• links to: GitHub Pull Request #3579
• links to: GitHub Pull Request #3593