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https://issues.apache.org/jira/browse/FLINK-10163?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16593513#comment-16593513
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ASF GitHub Bot commented on FLINK-10163:
----------------------------------------
twalthr commented on a change in pull request #6606: [FLINK-10163] [sql-client]
Support views in SQL Client
URL: https://github.com/apache/flink/pull/6606#discussion_r212942562
##########
File path: docs/dev/table/sqlClient.md
##########
@@ -459,6 +466,50 @@ Web interface: http://localhost:8081
{% top %}
+SQL Views
+---------
+
+Views allow to define virtual tables from SQL queries. The view definition is
parsed and validated immediately. However, the actual execution happens when
the view is accessed during the submission of a general `INSERT INTO` or
`SELECT` statement.
+
+Views can either be defined in [environment
files](sqlClient.html#environment-files) or within the CLI session.
+
+The following example shows how to define multiple views in a file:
+
+{% highlight yaml %}
+views:
+ - name: MyRestrictedView
+ query: "SELECT MyField2 FROM MyTableSource"
+ - name: MyComplexView
+ query: >
+ SELECT MyField2 + 42, CAST(MyField1 AS VARCHAR)
+ FROM MyTableSource
+ WHERE MyField2 > 200
+{% endhighlight %}
+
+Similar to table sources and sinks, views defined in a session environment
file have highest precendence.
+
+Views can also be created within a CLI session using the `CREATE VIEW`
statement:
+
+{% highlight text %}
+CREATE VIEW MyNewView AS SELECT MyField2 FROM MyTableSource
+{% endhighlight %}
+
+The `SHOW VIEW` statement allows for printing a previously created view again:
Review comment:
Listing views as regular tables in `SHOW TABLES` is also done in MySQL or
[Drill](https://drill.apache.org/docs/show-tables/). According to the
definition, a view is a "virtual table" and thus works for all table-related
operations. We can implement `SHOW FULL TABLES` in a follow-up issue that shows
more meta information. What do you think?
`DESCRIBE` should also have the same behavior in for both table and view (as
seen [here for
example](https://docs.oracle.com/javadb/10.8.3.0/tools/rtoolsijcomrefdescribe.html))
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> Support CREATE VIEW in SQL Client
> ---------------------------------
>
> Key: FLINK-10163
> URL: https://issues.apache.org/jira/browse/FLINK-10163
> Project: Flink
> Issue Type: New Feature
> Components: Table API & SQL
> Reporter: Timo Walther
> Assignee: Timo Walther
> Priority: Major
> Labels: pull-request-available
>
> The possibility to define a name for a subquery would improve the usability
> of the SQL Client. The SQL standard defines \{{CREATE VIEW}} for defining a
> virtual table.
>
> Example:
> {code}
> CREATE VIEW viewName
> [ '(' columnName [, columnName ]* ')' ]
> AS Query
> {code}
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