Package org.apache.flink.table.api

Interface GroupWindowedTable

@PublicEvolving public interface GroupWindowedTable
A table that has been windowed for GroupWindows.

  • Method Summary

    Modifier and Type
    Method
    Description
    WindowGroupedTable
    groupBy(org.apache.flink.table.expressions.Expression... fields)
    Groups the elements by a mandatory window and one or more optional grouping attributes.

  • Method Details

    • groupBy

      WindowGroupedTable groupBy(org.apache.flink.table.expressions.Expression... fields)
      Groups the elements by a mandatory window and one or more optional grouping attributes. The window is specified by referring to its alias.

      If no additional grouping attribute is specified and if the input is a streaming table, the aggregation will be performed by a single task, i.e., with parallelism 1.

      Aggregations are performed per group and defined by a subsequent select(...) clause similar to SQL SELECT-GROUP-BY query.

      Example: 

      
 tab.window([groupWindow].as("w")).groupBy($("w"), $("key")).select($("key"), $("value").avg());

      Scala Example: 

      
 tab.window([groupWindow] as 'w)).groupBy('w, 'key).select('key, 'value.avg)