a75dc80a76
### What changes were proposed in this pull request? Remove the unneeded embedded inline HTML markup by using the basic markdown syntax. Please see #28414 ### Why are the changes needed? Make the doc cleaner and easily editable by MD editors. ### Does this PR introduce _any_ user-facing change? No ### How was this patch tested? Manually build and check Closes #28451 from huaxingao/html_cleanup. Authored-by: Huaxin Gao <huaxing@us.ibm.com> Signed-off-by: Sean Owen <srowen@gmail.com>
140 lines
4 KiB
Markdown
140 lines
4 KiB
Markdown
---
|
|
layout: global
|
|
title: SHOW FUNCTIONS
|
|
displayTitle: SHOW FUNCTIONS
|
|
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
|
|
|
|
Returns the list of functions after applying an optional regex pattern.
|
|
Given number of functions supported by Spark is quite large, this statement
|
|
in conjunction with [describe function](sql-ref-syntax-aux-describe-function.html)
|
|
may be used to quickly find the function and understand its usage. The `LIKE`
|
|
clause is optional and supported only for compatibility with other systems.
|
|
|
|
### Syntax
|
|
|
|
```sql
|
|
SHOW [ function_kind ] FUNCTIONS [ [ LIKE ] { function_name | regex_pattern } ]
|
|
```
|
|
|
|
### Parameters
|
|
|
|
* **function_kind**
|
|
|
|
Specifies the name space of the function to be searched upon. The valid name spaces are :
|
|
|
|
* **USER** - Looks up the function(s) among the user defined functions.
|
|
* **SYSTEM** - Looks up the function(s) among the system defined functions.
|
|
* **ALL** - Looks up the function(s) among both user and system defined functions.
|
|
|
|
* **function_name**
|
|
|
|
Specifies a name of an existing function in the system. The function name may be
|
|
optionally qualified with a database name. If `function_name` is qualified with
|
|
a database then the function is resolved from the user specified database, otherwise
|
|
it is resolved from the current database.
|
|
|
|
**Syntax:** `[ database_name. ] function_name`
|
|
|
|
* **regex_pattern**
|
|
|
|
Specifies a regular expression pattern that is used to filter the results of the
|
|
statement.
|
|
|
|
* Except for `*` and `|` character, the pattern works like a regular expression.
|
|
* `*` alone matches 0 or more characters and `|` is used to separate multiple different regular expressions,
|
|
any of which can match.
|
|
* The leading and trailing blanks are trimmed in the input pattern before processing. The pattern match is case-insensitive.
|
|
|
|
### Examples
|
|
|
|
```sql
|
|
-- List a system function `trim` by searching both user defined and system
|
|
-- defined functions.
|
|
SHOW FUNCTIONS trim;
|
|
+--------+
|
|
|function|
|
|
+--------+
|
|
| trim|
|
|
+--------+
|
|
|
|
-- List a system function `concat` by searching system defined functions.
|
|
SHOW SYSTEM FUNCTIONS concat;
|
|
+--------+
|
|
|function|
|
|
+--------+
|
|
| concat|
|
|
+--------+
|
|
|
|
-- List a qualified function `max` from database `salesdb`.
|
|
SHOW SYSTEM FUNCTIONS salesdb.max;
|
|
+--------+
|
|
|function|
|
|
+--------+
|
|
| max|
|
|
+--------+
|
|
|
|
-- List all functions starting with `t`
|
|
SHOW FUNCTIONS LIKE 't*';
|
|
+-----------------+
|
|
| function|
|
|
+-----------------+
|
|
| tan|
|
|
| tanh|
|
|
| timestamp|
|
|
| tinyint|
|
|
| to_csv|
|
|
| to_date|
|
|
| to_json|
|
|
| to_timestamp|
|
|
|to_unix_timestamp|
|
|
| to_utc_timestamp|
|
|
| transform|
|
|
| transform_keys|
|
|
| transform_values|
|
|
| translate|
|
|
| trim|
|
|
| trunc|
|
|
| typeof|
|
|
+-----------------+
|
|
|
|
-- List all functions starting with `yea` or `windo`
|
|
SHOW FUNCTIONS LIKE 'yea*|windo*';
|
|
+--------+
|
|
|function|
|
|
+--------+
|
|
| window|
|
|
| year|
|
|
+--------+
|
|
|
|
-- Use normal regex pattern to list function names that has 4 characters
|
|
-- with `t` as the starting character.
|
|
SHOW FUNCTIONS LIKE 't[a-z][a-z][a-z]';
|
|
+--------+
|
|
|function|
|
|
+--------+
|
|
| tanh|
|
|
| trim|
|
|
+--------+
|
|
```
|
|
|
|
### Related Statements
|
|
|
|
* [DESCRIBE FUNCTION](sql-ref-syntax-aux-describe-function.html)
|