179289f0bf
### 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>
3.9 KiB
| layout | title | displayTitle | license |
|---|---|---|---|
| global | SHOW TBLPROPERTIES | SHOW TBLPROPERTIES | 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
This statement returns the value of a table property given an optional value for a property key. If no key is specified then all the properties are returned.
Syntax
{% highlight sql %} SHOW TBLPROPERTIES table_identifier [ ( unquoted_property_key | property_key_as_string_literal ) ] {% endhighlight %}
Parameters
table_identifier-
Specifies the table name of an existing table. The table may be optionally qualified
with a database name.
Syntax:[ database_name. ] table_name unquoted_property_key-
Specifies the property key in unquoted form. The key may consists of multiple
parts separated by dot.
Syntax:[ key_part1 ] [ .key_part2 ] [ ... ] property_key_as_string_literal- Specifies a property key value as a string literal.
Note
- Property value returned by this statement excludes some properties
that are internal to spark and hive. The excluded properties are :
- All the properties that start with prefix
spark.sql - Property keys such as:
EXTERNAL,comment - All the properties generated internally by hive to store statistics. Some of these
properties are:
numFiles,numPartitions,numRows.
- All the properties that start with prefix
Examples
{% highlight sql %}
-- create a table customer in database salesdb
USE salesdb;
CREATE TABLE customer(cust_code INT, name VARCHAR(100), cust_addr STRING)
TBLPROPERTIES ('created.by.user' = 'John', 'created.date' = '01-01-2001');
-- show all the user specified properties for table customer
SHOW TBLPROPERTIES customer;
+---------------------+----------+
| key| value|
+---------------------+----------+
| created.by.user| John|
| created.date|01-01-2001|
|transient_lastDdlTime|1567554931|
+---------------------+----------+
-- show all the user specified properties for a qualified table customer
-- in database salesdb
SHOW TBLPROPERTIES salesdb.customer;
+---------------------+----------+
| key| value|
+---------------------+----------+
| created.by.user| John|
| created.date|01-01-2001|
|transient_lastDdlTime|1567554931|
+---------------------+----------+
-- show value for unquoted property key created.by.user
SHOW TBLPROPERTIES customer (created.by.user);
+-----+
|value|
+-----+
| John|
+-----+
-- show value for property `created.date`` specified as string literal SHOW TBLPROPERTIES customer ('created.date'); +----------+ | value| +----------+ |01-01-2001| +----------+ {% endhighlight %}