dianfu commented on a change in pull request #8401: [FLINK-12407][python] Add
all table operators align Java Table API.
URL: https://github.com/apache/flink/pull/8401#discussion_r283169262
##########
File path: flink-python/pyflink/table/table.py
##########
@@ -118,3 +463,112 @@ def insert_into(self, table_name):
:param table_name: Name of the :class:`TableSink` to which the
:class:`Table` is written.
"""
self._j_table.insertInto(table_name)
+
+ def __str__(self):
+ return self._j_table.toString()
+
+
+class GroupedTable(object):
+ """
+ A table that has been grouped on a set of grouping keys.
+ """
+
+ def __init__(self, java_table):
+ self._j_table = java_table
+
+ def select(self, fields):
+ """
+ Performs a selection operation on a grouped table. Similar to an SQL
SELECT statement.
+ The field expressions can contain complex expressions and aggregations.
+
+ Example:
+ ::
+ >>> tab.group_by("key").select("key, value.avg + ' The average' as
average")
+
+
+ :param fields: Expression string that contains group keys and
aggregate function calls.
+ :return: Result table.
+ """
+ return Table(self._j_table.select(fields))
+
+
+class GroupWindowedTable(object):
+ """
+ A table that has been windowed for :class:`GroupWindow`s.
+ """
+
+ def __init__(self, java_group_windowed_table):
+ self._java_table = java_group_windowed_table
+
+ def group_by(self, 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
+ :func:`~pyflink.table.WindowGroupedTable.select` clause similar to SQL
SELECT-GROUP-BY
+ query.
+
+ Example:
+ ::
+ >>> tab.window(groupWindow.alias("w")).group_by("w,
key").select("key, value.avg")
+
+ :param fields: Group keys.
+ :return: A :class:`WindowGroupedTable`.
+ """
+ return WindowGroupedTable(self._java_table.groupBy(fields))
+
+
+class WindowGroupedTable(object):
+ """
+ A table that has been windowed and grouped for :class:`GroupWindow`s.
+ """
+
+ def __init__(self, java_window_grouped_table):
+ self._java_table = java_window_grouped_table
+
+ def select(self, fields):
+ """
+ Performs a selection operation on a window grouped table. Similar to
an SQL SELECT
+ statement.
+ The field expressions can contain complex expressions and aggregations.
+
+ Example:
+ ::
+ >>> window_grouped_table.select("key, window.start, value.avg as
valavg")
+
+ :param fields: Expression string.
+ :return: Result table.
+ """
+ return Table(self._java_table.select(fields))
+
+
+class OverWindowedTable(object):
+ """
+ A table that has been windowed for :class:`OverWindow`s.
+
+ Unlike group windows, which are specified in the GROUP BY clause, over
windows do not collapse
+ rows. Instead over window aggregates compute an aggregate for each input
row over a range of
+ its neighboring rows.
+ """
+
+ def __init__(self, java_over_windowed_table):
+ self._java_table = java_over_windowed_table
Review comment:
_java_table -> _j_over_windowed_table
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