hequn8128 commented on a change in pull request #7235: [FLINK-10976] [table]
Add support for aggregate to table API
URL: https://github.com/apache/flink/pull/7235#discussion_r240877558
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File path: docs/dev/table/tableApi.md
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@@ -1682,6 +1682,36 @@ The `OverWindow` defines a range of rows over which
aggregates are computed. `Ov
{% top %}
+### Aggregate
+
+Aggregate performs an aggregate operation with an aggregate function. You have
to close the
+"aggregate" with a select statement. The output will be flattened if the
output type is a
+composite type.
+
+<div class="codetabs" markdown="1">
+<div data-lang="java" markdown="1">
+{% highlight java %}
+tableEnv.registerFunction("myAggFunc", new MyAggregateFunction());
Review comment:
How about info user that `MyAggregateFunction` is an `AggregateFunction` by
define a variable: `AggregateFunction<?,?> myAggFunc = new
MyAggregateFunction()`. Same as the scala example. We will have Table aggregate
functions later. I think it would be nice if we distinguish them.
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