sunjincheng121 commented on a change in pull request #8057:
[FLINK-12028][table] Add `addColumns`,`renameColumns`, `dropColumns` …
URL: https://github.com/apache/flink/pull/8057#discussion_r270346847
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File path: docs/dev/table/tableApi.md
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@@ -188,7 +188,50 @@ Table result = orders.select("*");
{% endhighlight %}
</td>
</tr>
-
+ <tr>
+ <td>
+ <strong>AddColumns</strong><br>
+ <span class="label label-primary">Batch</span> <span class="label
label-primary">Streaming</span>
+ </td>
+ <td>
+ <p>Performs a field add operation.</p>
+{% highlight java %}
+Table orders = tableEnv.scan("Orders");
+Table result = orders.addColumns("concat(c, 'sunny')");
+{% endhighlight %}
+ <p>You can also replace existing fields, the following example
will replace the
+ existing `desc` field </p>
+{% highlight java %}
+Table result = orders.addColumns(true, "concat(c, 'sunny') as desc");
+{% endhighlight %}
+ </td>
+ </tr>
+ <tr>
+ <td>
+ <strong>DropColumns</strong><br>
+ <span class="label label-primary">Batch</span> <span
class="label label-primary">Streaming</span>
+ </td>
+ <td>
+ <p>Performs a field drop operation.</p>
+{% highlight java %}
+Table orders = tableEnv.scan("Orders");
+Table result = orders.dropColumns("b, c");
Review comment:
I think dropColumns only supports `FieldRefrence` or column operations, such
as `dropColunns(columns(...))` when FLINK-12029 is done. And It will throw an
exception If the column does not exist. The columns that the user wants to
delete are all known column names. If the user accidentally writes the wrong
column name but does not report an error, this will be a bit confusing, so I
chose strict verification if the column to be deleted does not exist, throw an
exception directly. Is that make sense to you?
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