[FLINK-13471] Add FlatAggregate support to stream Table API(blink planner)

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.10.0
• Fix Version/s: 1.10.0
• Component/s: Table SQL / API
• Labels: pull-request-available
• Assignee: sunjincheng
• Reporter: sunjincheng
• Created: 29/Jul/19 12:39
• Updated: 16/Apr/20 10:48
• Resolved: 16/Apr/20 10:48

Description

Add FlatAggregate support to stream Table API(blink planner), i.e, align with flink planner.
The API looks like:

 TableAggregateFunction tableAggFunc = new MyTableAggregateFunction();
 tableEnv.registerFunction("tableAggFunc", tableAggFunc);
tab.groupBy("key")
   .flatAggregate("tableAggFunc(a, b) as (x, y, z)")
   .select("key, x, y, z")

The detail can be found in Flip-29

Issue Links

• links to: GitHub Pull Request #9322