dianfu commented on a change in pull request #7209: [FLINK-10977][table] Add
UnBounded FlatAggregate operator to streaming Table API
URL: https://github.com/apache/flink/pull/7209#discussion_r240945195
##########
File path:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/api/table.scala
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@@ -1028,6 +1061,119 @@ class Table(
}
}
+class FlatAggTable(
+ private[flink] val table: Table,
+ private[flink] val tableAggCall: TableAggFunctionCall) {
+
+ /**
+ * Performs a selection operation on a FlatAggTable table. Similar to an
SQL SELECT statement.
+ * The field expressions can contain complex expressions.
+ *
+ * __Note__: You have to close the flatAggregate with a select statement.
And the select
+ * statement does not support * and aggregate functions.
+ *
+ * Example:
+ *
+ * {{{
+ * val tableAggFunc: TableAggregateFunction = new MyTableAggregateFunction
+ * tab.flatAggregate(tableAggFunc('a, 'b)).select(udf('_1), '_2, '_3)
+ * }}}
+ */
+ def select(fields: Expression*): Table = {
+ new GroupedFlatAggTable(table, Nil, tableAggCall).select(fields: _*)
+ }
+
+ /**
+ * Performs a selection operation on a FlatAggTable table. Similar to an
SQL SELECT statement.
+ * The field expressions can contain complex expressions.
+ *
+ * __Note__: You have to close the flatAggregate with a select statement.
And the select
+ * statement does not support * and aggregate functions.
+ *
+ * Example:
+ *
+ * {{{
+ * val tableAggFunc: TableAggregateFunction = new MyTableAggregateFunction
+ * tableEnv.registerFunction("myTableAggFunc", tableAggFunc);
+ * tab.flatAggregate("myTableAggFunc(a, b)").select("_1, _2, _3")
+ * }}}
+ */
+ def select(fields: String): Table = {
+ new GroupedFlatAggTable(table, Nil, tableAggCall).select(fields)
+ }
+}
+
+/**
+ * A table that has been grouped on a set of grouping keys and perform
flatAggregate.
+ */
+class GroupedFlatAggTable(
+ private[flink] val table: Table,
+ private[flink] val groupKey: Seq[Expression],
+ private[flink] val tableAggCall: TableAggFunctionCall) {
+
+ /**
+ * Performs a selection operation on a GroupedFlatAggTable table. Similar
to an SQL SELECT
+ * statement. The field expressions can contain complex expressions.
+ *
+ * __Note__: You have to close the flatAggregate with a select statement.
And the select
+ * statement does not support * and aggregate functions.
+ *
+ * Example:
+ *
+ * {{{
+ * val tableAggFunc: TableAggregateFunction = new MyTableAggregateFunction
+ * tab.groupBy('key).flatAggregate(tableAggFunc('a, 'b)).select(udf('_1),
'_2, '_3)
+ * }}}
+ */
+ def select(fields: Expression*): Table = {
+ val expandedFields = expandProjectList(tableAggCall.args,
table.logicalPlan, table.tableEnv)
+ val projectFields = extractFieldReferences(expandedFields ++ groupKey)
+
+ val flatAggTable = new Table(table.tableEnv,
+ TableAggregate(groupKey, tableAggCall,
+ Project(projectFields, table.logicalPlan).validate(table.tableEnv)
+ ).validate(table.tableEnv))
+
+ // check no '*' in the select of flatAggregate.
Review comment:
Why * is not supported? I think * should not be supported currently in group
window case. Right?
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