[GitHub] [spark] juliuszsompolski commented on a change in pull request #27897: [SPARK-31113][SQL] Add SHOW VIEWS command

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juliuszsompolski commented on a change in pull request #27897: [SPARK-31113][SQL] Add SHOW VIEWS command
URL: https://github.com/apache/spark/pull/27897#discussion_r399173962
 
 

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 File path: docs/sql-ref-syntax-aux-show-views.md
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+---
+layout: global
+title: SHOW VIEWS
+displayTitle: SHOW VIEWS
+license: |
+  Licensed to the Apache Software Foundation (ASF) under one or more
+  contributor license agreements.  See the NOTICE file distributed with
+  this work for additional information regarding copyright ownership.
+  The ASF licenses this file to You under the Apache License, Version 2.0
+  (the "License"); you may not use this file except in compliance with
+  the License.  You may obtain a copy of the License at
+ 
+     http://www.apache.org/licenses/LICENSE-2.0
+ 
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+---
+### Description
+
+The `SHOW VIEWS` statement returns all the views for an optionally specified database.
+Additionally, the output of this statement may be filtered by an optional matching
+pattern. If no database is specified then the views are returned from the 
+current database. Note that the command always lists global and temporary views 
+regardless of a given database.
+
+### Syntax
+{% highlight sql %}
+SHOW VIEWS [ { FROM | IN } database_name ] [ LIKE 'regex_pattern' ]
+{% endhighlight %}
+
+### Parameters
+<dl>
+  <dt><code><em>{ FROM | IN } database_name</em></code></dt>
+  <dd>
+     Specifies the database name from which views are listed.
+  </dd>
+  <dt><code><em>LIKE regex_pattern</em></code></dt>
+  <dd>
+     Specifies the regular expression pattern that is used to filter out unwanted views. 
+     <ul> 
+          <li> Except for `*` and `|` character, the pattern works like a regex.</li>
+          <li> `*` alone matches 0 or more characters and `|` is used to separate multiple different regexes,
+           any of which can match. </li>
+          <li> The leading and trailing blanks are trimmed in the input pattern before processing.</li>
+     </ul>
+  </dd>
+</dl>
+
+### Example
+{% highlight sql %}
+-- Create views in different databases, also create global/local temp views.
+CREATE VIEW sam AS SELECT id, salary FROM employee WHERE name = 'sam';
+CREATE VIEW sam1 AS SELECT id, salary FROM employee WHERE name = 'sam1';
+CREATE VIEW suj AS SELECT id, salary FROM employee WHERE name = 'suj';
+USE userdb;
+CREATE VIEW user1 AS SELECT id, salary FROM employee WHERE name = 'user1';
+CREATE VIEW user2 AS SELECT id, salary FROM employee WHERE name = 'user2';
+USE default;
+CREATE GLOBAL TEMP VIEW temp1 AS SELECT 1 as col1;
+CREATE TEMP VIEW temp2 AS SELECT 1 as col1;
+
+-- List all views in default database
+SHOW VIEWS;
+  +-------------+------------+--------------+--+
+  | database    | viewName   | isTemporary  |
+  +-------------+------------+--------------+--+
+  | default     | sam        | false        |
+  | default     | sam1       | false        |
+  | default     | suj        | false        |
+  | global_temp | temp1      | true         |
 
 Review comment:
   +1 to @cloud-fan comment. We should only return global temp views if schema pattern matches global_temp name.

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