75da05038b
### What changes were proposed in this pull request? Remove two leading spaces from sql tables. ### Why are the changes needed? Follow the format of other references such as https://docs.snowflake.com/en/sql-reference/constructs/join.html, https://docs.oracle.com/cd/B19306_01/server.102/b14200/statements_10002.htm, https://www.postgresql.org/docs/10/sql-select.html. ### Does this PR introduce any user-facing change? before ``` SELECT * FROM test; +-+ ... +-+ ``` after ``` SELECT * FROM test; +-+ ... +-+ ``` ### How was this patch tested? Manually build and check Closes #28348 from huaxingao/sql-format. Authored-by: Huaxin Gao <huaxing@us.ibm.com> Signed-off-by: gatorsmile <gatorsmile@gmail.com>
146 lines
4.3 KiB
Markdown
146 lines
4.3 KiB
Markdown
---
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layout: global
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title: SHOW FUNCTIONS
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displayTitle: SHOW FUNCTIONS
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license: |
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Licensed to the Apache Software Foundation (ASF) under one or more
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contributor license agreements. See the NOTICE file distributed with
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this work for additional information regarding copyright ownership.
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The ASF licenses this file to You under the Apache License, Version 2.0
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(the "License"); you may not use this file except in compliance with
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the License. You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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---
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### Description
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Returns the list of functions after applying an optional regex pattern.
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Given number of functions supported by Spark is quite large, this statement
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in conjunction with [describe function](sql-ref-syntax-aux-describe-function.html)
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may be used to quickly find the function and understand its usage. The `LIKE`
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clause is optional and supported only for compatibility with other systems.
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### Syntax
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{% highlight sql %}
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SHOW [ function_kind ] FUNCTIONS ( [ LIKE ] function_name | regex_pattern )
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{% endhighlight %}
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### Parameters
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<dl>
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<dt><code><em>function_kind</em></code></dt>
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<dd>
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Specifies the name space of the function to be searched upon. The valid name spaces are :
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<ul>
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<li><b>USER</b> - Looks up the function(s) among the user defined functions.</li>
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<li><b>SYSTEM</b> - Looks up the function(s) among the system defined functions.</li>
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<li><b>ALL</b> - Looks up the function(s) among both user and system defined functions.</li>
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</ul>
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</dd>
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<dt><code><em>function_name</em></code></dt>
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<dd>
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Specifies a name of an existing function in the system. The function name may be
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optionally qualified with a database name. If `function_name` is qualified with
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a database then the function is resolved from the user specified database, otherwise
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it is resolved from the current database.<br><br>
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<b>Syntax:</b>
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<code>
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[database_name.]function_name
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</code>
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</dd>
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<dt><code><em>regex_pattern</em></code></dt>
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<dd>
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Specifies a regular expression pattern that is used to filter the results of the
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statement.
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<ul>
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<li>Only <code>*</code> and <code>|</code> are allowed as wildcard pattern.</li>
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<li>Excluding <code>*</code> and <code>|</code>, the remaining pattern follows the regular expression semantics.</li>
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<li>The leading and trailing blanks are trimmed in the input pattern before processing. The pattern match is case-insensitive.</li>
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</ul>
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</dd>
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</dl>
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### Examples
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{% highlight sql %}
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-- List a system function `trim` by searching both user defined and system
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-- defined functions.
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SHOW FUNCTIONS trim;
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+--------+
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|function|
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+--------+
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| trim|
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+--------+
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-- List a system function `concat` by searching system defined functions.
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SHOW SYSTEM FUNCTIONS concat;
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+--------+
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|function|
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+--------+
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| concat|
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+--------+
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-- List a qualified function `max` from database `salesdb`.
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SHOW SYSTEM FUNCTIONS salesdb.max;
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+--------+
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|function|
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+--------+
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| max|
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+--------+
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-- List all functions starting with `t`
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SHOW FUNCTIONS LIKE 't*';
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+-----------------+
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| function|
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+-----------------+
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| tan|
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| tanh|
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| timestamp|
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| tinyint|
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| to_csv|
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| to_date|
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| to_json|
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| to_timestamp|
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|to_unix_timestamp|
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| to_utc_timestamp|
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| transform|
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| transform_keys|
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| transform_values|
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| translate|
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| trim|
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| trunc|
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| typeof|
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+-----------------+
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-- List all functions starting with `yea` or `windo`
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SHOW FUNCTIONS LIKE 'yea*|windo*';
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+--------+
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|function|
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+--------+
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| window|
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| year|
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+--------+
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-- Use normal regex pattern to list function names that has 4 characters
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-- with `t` as the starting character.
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SHOW FUNCTIONS LIKE 't[a-z][a-z][a-z]';
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+--------+
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|function|
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+--------+
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| tanh|
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| trim|
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+--------+
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{% endhighlight %}
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### Related Statements
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* [DESCRIBE FUNCTION](sql-ref-syntax-aux-describe-function.html)
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