Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/4585#discussion_r141113194
--- Diff: docs/dev/table/sql.md ---
@@ -2107,6 +2108,17 @@ VAR_SAMP(value)
<p>Returns the sample variance (square of the sample standard
deviation) of the numeric field across all input values.</p>
</td>
</tr>
+
+ <tr>
+ <td>
+ {% highlight text %}
+ COLLECT(value)
+ {% endhighlight %}
+ </td>
+ <td>
+ <p>Returns a multiset of the <i>value</i>s.</p>
--- End diff --
Be more specific about the handling of `null` values. Are they ignored?
What is returned if only null values are added (`null` or empty multiset)?
---
