69b0cc1962
### What changes were proposed in this pull request? Add DROP FUNCTION sql description in SQL reference ### Why are the changes needed? Currently from spark there is no complete sql guide is present, so it is better to document all the sql commands, this jira is sub part of this task. ### Does this PR introduce any user-facing change? Yes before user cannot find any reference for drop function command in the spark docs. After Fix: ![image](https://user-images.githubusercontent.com/35216143/66134570-240cd300-e616-11e9-9c78-259c0d355378.png) ![image](https://user-images.githubusercontent.com/35216143/65397825-d059e880-ddd0-11e9-8bd3-a65ccae56063.png) ![image](https://user-images.githubusercontent.com/35216143/66404731-9f032e80-ea06-11e9-8fef-1e266efa4c66.png) ### How was this patch tested? tested with jekyll build Closes #25553 from sandeep-katta/28797. Authored-by: sandeep katta <sandeep.katta2007@gmail.com> Signed-off-by: Sean Owen <sean.owen@databricks.com>
105 lines
3 KiB
Markdown
105 lines
3 KiB
Markdown
---
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layout: global
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title: DROP FUNCTION
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displayTitle: DROP FUNCTION
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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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The `DROP FUNCTION` statement drops a temporary or user defined function (UDF). An exception will
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be thrown if the function does not exist.
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### Syntax
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{% highlight sql %}
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DROP [TEMPORARY] FUNCTION [IF EXISTS] [db_name.]function_name;
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{% endhighlight %}
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### Parameters
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<dl>
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<dt><code><em>function_name</em></code></dt>
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<dd>The name of an existing function.</dd>
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</dl>
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<dl>
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<dt><code><em>TEMPORARY</em></code></dt>
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<dd>Should be used to delete the `temporary` function.</dd>
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</dl>
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<dl>
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<dt><code><em>IF EXISTS</em></code></dt>
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<dd>If specified, no exception is thrown when the function does not exist.</dd>
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</dl>
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### Example
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{% highlight sql %}
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-- Create a permanent function `test_avg`
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CREATE FUNCTION test_avg as 'org.apache.hadoop.hive.ql.udf.generic.GenericUDAFAverage';
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-- List user functions
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SHOW USER FUNCTIONS;
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+-------------------+
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| function |
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+-------------------+
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| default.test_avg |
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+-------------------+
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-- Create Temporary function `test_avg`
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CREATE TEMPORARY FUNCTION test_avg as 'org.apache.hadoop.hive.ql.udf.generic.GenericUDAFAverage';
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-- List user functions
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SHOW USER FUNCTIONS;
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+-------------------+
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| function |
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+-------------------+
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| default.test_avg |
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| test_avg |
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+-------------------+
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-- Drop Permanent function
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DROP FUNCTION test_avg;
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+---------+
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| Result |
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+---------+
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+---------+
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-- Try to drop Permanent function which is not present
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DROP FUNCTION test_avg;
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Error: Error running query:
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org.apache.spark.sql.catalyst.analysis.NoSuchPermanentFunctionException:
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Function 'default.test_avg' not found in database 'default'; (state=,code=0)
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-- List the functions after dropping, it should list only temporary function
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SHOW USER FUNCTIONS;
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+-----------+
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| function |
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+-----------+
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| test_avg |
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+-----------+
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-- Drop Temporary function
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DROP TEMPORARY FUNCTION IF EXISTS test_avg;
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+---------+
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| Result |
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+---------+
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+---------+
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{% endhighlight %}
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### Related statements
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- [CREATE FUNCTION](sql-ref-syntax-ddl-create-function.html)
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- [DESCRIBE FUNCTION](sql-ref-syntax-aux-describe-function.html)
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- [SHOW FUNCTION](sql-ref-syntax-aux-show-functions.html) |