2019-08-19 02:17:50 -04:00
---
layout: global
2020-01-31 13:52:22 -05:00
title: Data Definition Statements
displayTitle: Data Definition Statements
2019-08-19 02:17:50 -04:00
license: |
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---
2020-01-31 13:52:22 -05:00
Data Definition Statements are used to create or modify the structure of database objects in a database. Spark SQL supports the following Data Definition Statements:
[SPARK-31383][SQL][DOC] Clean up the SQL documents in docs/sql-ref*
### What changes were proposed in this pull request?
This PR intends to clean up the SQL documents in `doc/sql-ref*`.
Main changes are as follows;
- Fixes wrong syntaxes and capitalize sub-titles
- Adds some DDL queries in `Examples` so that users can run examples there
- Makes query output in `Examples` follows the `Dataset.showString` (right-aligned) format
- Adds/Removes spaces, Indents, or blank lines to follow the format below;
```
---
license...
---
### Description
Writes what's the syntax is.
### Syntax
{% highlight sql %}
SELECT...
WHERE... // 4 indents after the second line
...
{% endhighlight %}
### Parameters
<dl>
<dt><code><em>Param Name</em></code></dt>
<dd>
Param Description
</dd>
...
</dl>
### Examples
{% highlight sql %}
-- It is better that users are able to execute example queries here.
-- So, we prepare test data in the first section if possible.
CREATE TABLE t (key STRING, value DOUBLE);
INSERT INTO t VALUES
('a', 1.0), ('a', 2.0), ('b', 3.0), ('c', 4.0);
-- query output has 2 indents and it follows the `Dataset.showString`
-- format (right-aligned).
SELECT * FROM t;
+---+-----+
|key|value|
+---+-----+
| a| 1.0|
| a| 2.0|
| b| 3.0|
| c| 4.0|
+---+-----+
-- Query statements after the second line have 4 indents.
SELECT key, SUM(value)
FROM t
GROUP BY key;
+---+----------+
|key|sum(value)|
+---+----------+
| c| 4.0|
| b| 3.0|
| a| 3.0|
+---+----------+
...
{% endhighlight %}
### Related Statements
* [XXX](xxx.html)
* ...
```
### Why are the changes needed?
The most changes of this PR are pretty minor, but I think the consistent formats/rules to write documents are important for long-term maintenance in our community
### Does this PR introduce any user-facing change?
Yes.
### How was this patch tested?
Manually checked.
Closes #28151 from maropu/MakeRightAligned.
Authored-by: Takeshi Yamamuro <yamamuro@apache.org>
Signed-off-by: Sean Owen <srowen@gmail.com>
2020-04-13 00:40:36 -04:00
* [ALTER DATABASE ](sql-ref-syntax-ddl-alter-database.html )
* [ALTER TABLE ](sql-ref-syntax-ddl-alter-table.html )
* [ALTER VIEW ](sql-ref-syntax-ddl-alter-view.html )
* [CREATE DATABASE ](sql-ref-syntax-ddl-create-database.html )
* [CREATE FUNCTION ](sql-ref-syntax-ddl-create-function.html )
* [CREATE TABLE ](sql-ref-syntax-ddl-create-table.html )
* [CREATE VIEW ](sql-ref-syntax-ddl-create-view.html )
* [DROP DATABASE ](sql-ref-syntax-ddl-drop-database.html )
* [DROP FUNCTION ](sql-ref-syntax-ddl-drop-function.html )
* [DROP TABLE ](sql-ref-syntax-ddl-drop-table.html )
* [DROP VIEW ](sql-ref-syntax-ddl-drop-view.html )
* [TRUNCATE TABLE ](sql-ref-syntax-ddl-truncate-table.html )
* [REPAIR TABLE ](sql-ref-syntax-ddl-repair-table.html )
2020-07-04 22:01:07 -04:00
* [USE DATABASE ](sql-ref-syntax-ddl-usedb.html )
