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_r284615491
##########
File path: flink-python/pyflink/table/table.py
##########
@@ -96,16 +105,413 @@ def where(self, predicate):
"""
Filters out elements that don't pass the filter predicate. Similar to
a SQL WHERE
clause.
+
Example:
::
-
>>> tab.where("name = 'Fred'")
:param predicate: Predicate expression string.
:return: Result table.
"""
return Table(self._j_table.where(predicate))
+ def group_by(self, fields):
+ """
+ Groups the elements on some grouping keys. Use this before a selection
with aggregations
+ to perform the aggregation on a per-group basis. Similar to a SQL
GROUP BY statement.
+
+ Example:
+ ::
+ >>> tab.group_by("key").select("key, value.avg")
+
+ :param fields: Group keys.
+ :return: The grouped table.
+ """
+ return GroupedTable(self._j_table.groupBy(fields))
+
+ def distinct(self):
+ """
+ Removes duplicate values and returns only distinct (different) values.
+
+ Example:
+ ::
+ >>> tab.select("key, value").distinct()
+
+ :return: Result table.
+ """
+ return Table(self._j_table.distinct())
+
+ def join(self, right, join_predicate=None):
+ """
+ Joins two :class:`Table`s. Similar to a SQL join. The fields of the
two joined
+ operations must not overlap, use :func:`~pyflink.table.Table.alias` to
rename fields if
+ necessary. You can use where and select clauses after a join to
further specify the
+ behaviour of the join.
+
+ .. note::
+ Both tables must be bound to the same :class:`TableEnvironment` .
+
+ Example:
+ ::
+ >>> left.join(right).where("a = b && c > 3").select("a, b, d")
+ >>> left.join(right, "a = b")
+
+ :param right: Right table.
+ :param join_predicate: Optional, the join predicate expression string.
+ :return: Result table.
+ """
+ if join_predicate is not None:
+ return Table(self._j_table.join(right._j_table, join_predicate))
+ else:
+ return Table(self._j_table.join(right._j_table))
+
+ def left_outer_join(self, right, join_predicate=None):
+ """
+ Joins two :class:`Table`s. Similar to a SQL left outer join. The
fields of the two joined
+ operations must not overlap, use :func:`~pyflink.table.Table.alias` to
rename fields if
+ necessary.
+
+ .. note::
+ Both tables must be bound to the same :class:`TableEnvironment`
and its
+ :class:`TableConfig` must have null check enabled (default).
+
+ Example:
+ ::
+ >>> left.left_outer_join(right).select("a, b, d")
+ >>> left.left_outer_join(right, "a = b").select("a, b, d")
+
+ :param right: Right table.
+ :param join_predicate: Optional, the join predicate expression string.
+ :return: Result table.
+ """
+ if join_predicate is None:
+ return Table(self._j_table.leftOuterJoin(right._j_table))
+ else:
+ return Table(self._j_table.leftOuterJoin(right._j_table,
join_predicate))
+
+ def right_outer_join(self, right, join_predicate):
+ """
+ Joins two :class:`Table`s. Similar to a SQL right outer join. The
fields of the two joined
+ operations must not overlap, use :func:`~pyflink.table.Table.alias` to
rename fields if
+ necessary.
+
+ .. note::
+ Both tables must be bound to the same :class:`TableEnvironment`
and its
+ :class:`TableConfig` must have null check enabled (default).
+
+ Example:
+ ::
+ >>> left.right_outer_join(right, "a = b").select("a, b, d")
+
+ :param right: Right table.
+ :param join_predicate: The join predicate expression string.
+ :return: Result table.
+ """
+ return Table(self._j_table.rightOuterJoin(right._j_table,
join_predicate))
+
+ def full_outer_join(self, right, join_predicate):
+ """
+ Joins two :class:`Table`s. Similar to a SQL full outer join. The
fields of the two joined
+ operations must not overlap, use :func:`~pyflink.table.Table.alias` to
rename fields if
+ necessary.
+
+ .. note::
+ Both tables must be bound to the same :class:`TableEnvironment`
and its
+ :class:`TableConfig` must have null check enabled (default).
+
+ Example:
+ ::
+ >>> left.full_outer_join(right, "a = b").select("a, b, d")
+
+ :param right: Right table.
+ :param join_predicate: The join predicate expression string.
+ :return: Result table.
+ """
+ return Table(self._j_table.fullOuterJoin(right._j_table,
join_predicate))
+
+ def minus(self, right):
+ """
+ Minus of two :class:`Table`s with duplicate records removed.
+ Similar to a SQL EXCEPT clause. Minus returns records from the left
table that do not
+ exist in the right table. Duplicate records in the left table are
returned
+ exactly once, i.e., duplicates are removed. Both tables must have
identical field types.
+
+ .. note::
+ Both tables must be bound to the same :class:`TableEnvironment`.
+
+ Example:
+ ::
+ >>> left.minus(right)
+
+ :param right: Right table.
+ :return: Result table.
+ """
+ return Table(self._j_table.minus(right._j_table))
+
+ def minus_all(self, right):
+ """
+ Minus of two :class:`Table`s. Similar to a SQL EXCEPT ALL.
+ Similar to a SQL EXCEPT ALL clause. MinusAll returns the records that
do not exist in
+ the right table. A record that is present n times in the left table
and m times
+ in the right table is returned (n - m) times, i.e., as many duplicates
as are present
+ in the right table are removed. Both tables must have identical field
types.
+
+ .. note::
+ Both tables must be bound to the same :class:`TableEnvironment`.
+
+ Example:
+ ::
+ >>> left.minus_all(right)
+
+ :param right: Right table.
+ :return: Result table.
+ """
+ return Table(self._j_table.minusAll(right._j_table))
+
+ def union(self, right):
+ """
+ Unions two :class:`Table`s with duplicate records removed.
+ Similar to a SQL UNION. The fields of the two union operations must
fully overlap.
+
+ .. note::
+ Both tables must be bound to the same :class:`TableEnvironment`.
+
+ Example:
+ ::
+ >>> left.union(right)
+
+ :param right: Right table.
+ :return: Result table.
+ """
+ return Table(self._j_table.union(right._j_table))
+
+ def union_all(self, right):
+ """
+ Unions two :class:`Table`s. Similar to a SQL UNION ALL. The fields of
the two union
+ operations must fully overlap.
+
+ .. note::
+ Both tables must be bound to the same :class:`TableEnvironment`.
+
+ Example:
+ ::
+ >>> left.union_all(right)
+
+ :param right: Right table.
+ :return: Result table.
+ """
+ return Table(self._j_table.unionAll(right._j_table))
+
+ def intersect(self, right):
+ """
+ Intersects two :class:`Table`s with duplicate records removed.
Intersect returns records
+ that exist in both tables. If a record is present in one or both
tables more than once,
+ it is returned just once, i.e., the resulting table has no duplicate
records. Similar to a
+ SQL INTERSECT. The fields of the two intersect operations must fully
overlap.
+
+ .. note::
+ Both tables must be bound to the same :class:`TableEnvironment`.
+
+ Example:
+ ::
+ >>> left.intersect(right)
+
+ :param right: Right table.
+ :return: Result table.
+ """
+ return Table(self._j_table.intersect(right._j_table))
+
+ def intersect_all(self, right):
+ """
+ Intersects two :class:`Table`s. IntersectAll returns records that
exist in both tables.
+ If a record is present in both tables more than once, it is returned
as many times as it
+ is present in both tables, i.e., the resulting table might have
duplicate records. Similar
+ to an SQL INTERSECT ALL. The fields of the two intersect operations
must fully overlap.
+
+ .. note::
+ Both tables must be bound to the same :class:`TableEnvironment`.
+
+ Example:
+ ::
+ >>> left.intersect_all(right)
+
+ :param right: Right table.
+ :return: Result table.
+ """
+ return Table(self._j_table.intersectAll(right._j_table))
+
+ def order_by(self, fields):
+ """
+ Sorts the given :class:`Table`. Similar to SQL ORDER BY.
+ The resulting Table is sorted globally sorted across all parallel
partitions.
+
+ Example:
+ ::
+ >>> tab.order_by("name.desc")
+
+ :param fields: Order fields expression string,
+ :return: Result table.
+ """
+ return Table(self._j_table.orderBy(fields))
+
+ def offset(self, offset):
+ """
+ Limits a sorted result from an offset position.
+ Similar to a SQL OFFSET clause. Offset is technically part of the
Order By operator and
+ thus must be preceded by it.
+ :func:`~pyflink.table.Table.offset` can be combined with a subsequent
+ :func:`~pyflink.table.Table.fetch` call to return n rows after
skipping the first o rows.
+
+ Example:
+ ::
+ # skips the first 3 rows and returns all following rows.
+ >>> tab.order_by("name.desc").offset(3)
+ # skips the first 10 rows and returns the next 5 rows.
+ >>> tab.order_by("name.desc").offset(10).fetch(5)
+
+ :param offset: Number of records to skip.
+ :return: Result table.
+ """
+ return Table(self._j_table.offset(offset))
+
+ def fetch(self, fetch):
+ """
+ Limits a sorted result to the first n rows.
+ Similar to a SQL FETCH clause. Fetch is technically part of the Order
By operator and
+ thus must be preceded by it.
+ :func:`~pyflink.table.Table.offset` can be combined with a preceding
+ :func:`~pyflink.table.Table.fetch` call to return n rows after
skipping the first o rows.
+
+ Example:
+
+ Returns the first 3 records.
+ ::
+ >>> tab.order_by("name.desc").fetch(3)
+
+ Skips the first 10 rows and returns the next 5 rows.
+ ::
+ >>> tab.order_by("name.desc").offset(10).fetch(5)
+
+ :param fetch: The number of records to return. Fetch must be >= 0.
+ :return: Result table.
+ """
+ return Table(self._j_table.fetch(fetch))
+
+ def window(self, window):
+ """
+ Defines group window on the records of a table.
+
+ A group window groups the records of a table by assigning them to
windows defined by a time
+ or row interval.
+
+ For streaming tables of infinite size, grouping into windows is
required to define finite
+ groups on which group-based aggregates can be computed.
+
+ For batch tables of finite size, windowing essentially provides
shortcuts for time-based
+ groupBy.
+
+ .. note::
+ Computing windowed aggregates on a streaming table is only a
parallel operation
+ if additional grouping attributes are added to the
+ :func:`~pyflink.table.GroupWindowedTable.group_by` clause.
+ If the :func:`~pyflink.table.GroupWindowedTable.group_by` only
references a GroupWindow
+ alias, the streamed table will be processed by a single task,
i.e., with parallelism 1.
+
+ :param windows: A :class:`GroupWindow` created from :class:`Tumble`,
:class:`Session` or
+ :class:`Slide`.
+ :return: A :class:`GroupWindowedTable`.
+ """
+ # type: (GroupWindow) -> GroupWindowedTable
+ return GroupWindowedTable(self._j_table.window(window._java_window))
+
+ def over_window(self, *over_windows):
+ """
+ Defines over-windows on the records of a table.
+
+ An over-window defines for each record an interval of records over
which aggregation
+ functions can be computed.
+
+ Example:
+ ::
+ >>> table.window(Over.partition_by("c").order_by("rowTime")\
+ ... .preceding("10.seconds").alias("ow"))\
+ ... .select("c, b.count over ow, e.sum over ow")
+
+ .. note::
+ Computing over window aggregates on a streaming table is only a
parallel
+ operation if the window is partitioned. Otherwise, the whole
stream will be processed
+ by a single task, i.e., with parallelism 1.
+
+ .. note::
+ Over-windows for batch tables are currently not supported.
+
+ :param windows: :class:`OverWindow`s created from :class:`Over`.
Review comment:
windows -> over_windows
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