spark-instrumented-optimizer/docs/sql-ref-syntax-aux-conf-mgmt-set.md
sharangk c6ca66113f [SPARK-28814][SQL][DOC] Document SET/RESET in SQL Reference
### What changes were proposed in this pull request?
Document SET/REST statement in SQL Reference Guide.

### Why are the changes needed?
Currently Spark lacks documentation on the supported SQL constructs causing
confusion among users who sometimes have to look at the code to understand the
usage. This is aimed at addressing this issue.

### Does this PR introduce any user-facing change?
Yes.

#### Before:
There was no documentation for this.

#### After:

**SET**
![image](https://user-images.githubusercontent.com/29914590/65037551-94a3c680-d96b-11e9-9d59-9f7af5185e06.png)
![image](https://user-images.githubusercontent.com/29914590/64858792-fb607180-d645-11e9-8a53-8cf87a166fc1.png)

**RESET**
![image](https://user-images.githubusercontent.com/29914590/64859019-b12bc000-d646-11e9-8cb4-73dc21830067.png)

### How was this patch tested?
Manual Review and Tested using jykyll build --serve

Closes #25606 from sharangk/resetDoc.

Authored-by: sharangk <sharan.gk@gmail.com>
Signed-off-by: Xiao Li <gatorsmile@gmail.com>
2019-09-17 14:36:56 -07:00

70 lines
2.2 KiB
Markdown

---
layout: global
title: SET
displayTitle: SET
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 SET command sets a property, returns the value of an existing property or returns all SQLConf properties with value and meaning.
### Syntax
{% highlight sql %}
SET
SET [ -v ]
SET property_key[ = property_value ]
{% endhighlight %}
### Parameters
<dl>
<dt><code><em>-v</em></code></dt>
<dd>Outputs the key, value and meaning of existing SQLConf properties.</dd>
</dl>
<dl>
<dt><code><em>property_key</em></code></dt>
<dd>Returns the value of specified property key.</dd>
</dl>
<dl>
<dt><code><em>property_key=property_value</em></code></dt>
<dd>Sets the value for a given property key. If an old value exists for a given property key, then it gets overridden by the new value.</dd>
</dl>
### Examples
{% highlight sql %}
-- Set a property.
SET spark.sql.variable.substitute=false;
-- List all SQLConf properties with value and meaning.
SET -v;
-- List all SQLConf properties with value for current session.
SET;
-- List the value of specified property key.
SET spark.sql.variable.substitute;
+--------------------------------+--------+
| key | value |
+--------------------------------+--------+
| spark.sql.variable.substitute | false |
+--------------------------------+--------+
{% endhighlight %}
### Related Statements
- [RESET](sql-ref-syntax-aux-conf-mgmt-reset.html)