0001 ---
0002 layout: global
0003 title: DROP FUNCTION
0004 displayTitle: DROP FUNCTION
0005 license: |
0006 Licensed to the Apache Software Foundation (ASF) under one or more
0007 contributor license agreements. See the NOTICE file distributed with
0008 this work for additional information regarding copyright ownership.
0009 The ASF licenses this file to You under the Apache License, Version 2.0
0010 (the "License"); you may not use this file except in compliance with
0011 the License. You may obtain a copy of the License at
0012
0013 http://www.apache.org/licenses/LICENSE-2.0
0014
0015 Unless required by applicable law or agreed to in writing, software
0016 distributed under the License is distributed on an "AS IS" BASIS,
0017 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
0018 See the License for the specific language governing permissions and
0019 limitations under the License.
0020 ---
0021
0022 ### Description
0023
0024 The `DROP FUNCTION` statement drops a temporary or user defined function (UDF). An exception will
0025 be thrown if the function does not exist.
0026
0027 ### Syntax
0028
0029 ```sql
0030 DROP [ TEMPORARY ] FUNCTION [ IF EXISTS ] function_name
0031 ```
0032
0033 ### Parameters
0034
0035 * **function_name**
0036
0037 Specifies the name of an existing function. The function name may be
0038 optionally qualified with a database name.
0039
0040 **Syntax:** `[ database_name. ] function_name`
0041
0042 * **TEMPORARY**
0043
0044 Should be used to delete the `TEMPORARY` function.
0045
0046 * **IF EXISTS**
0047
0048 If specified, no exception is thrown when the function does not exist.
0049
0050 ### Examples
0051
0052 ```sql
0053 -- Create a permanent function `test_avg`
0054 CREATE FUNCTION test_avg AS 'org.apache.hadoop.hive.ql.udf.generic.GenericUDAFAverage';
0055
0056 -- List user functions
0057 SHOW USER FUNCTIONS;
0058 +----------------+
0059 | function|
0060 +----------------+
0061 |default.test_avg|
0062 +----------------+
0063
0064 -- Create Temporary function `test_avg`
0065 CREATE TEMPORARY FUNCTION test_avg AS
0066 'org.apache.hadoop.hive.ql.udf.generic.GenericUDAFAverage';
0067
0068 -- List user functions
0069 SHOW USER FUNCTIONS;
0070 +----------------+
0071 | function|
0072 +----------------+
0073 |default.test_avg|
0074 | test_avg|
0075 +----------------+
0076
0077 -- Drop Permanent function
0078 DROP FUNCTION test_avg;
0079
0080 -- Try to drop Permanent function which is not present
0081 DROP FUNCTION test_avg;
0082 Error: Error running query:
0083 org.apache.spark.sql.catalyst.analysis.NoSuchPermanentFunctionException:
0084 Function 'default.test_avg' not found in database 'default'; (state=,code=0)
0085
0086 -- List the functions after dropping, it should list only temporary function
0087 SHOW USER FUNCTIONS;
0088 +--------+
0089 |function|
0090 +--------+
0091 |test_avg|
0092 +--------+
0093
0094 -- Drop Temporary function
0095 DROP TEMPORARY FUNCTION IF EXISTS test_avg;
0096 ```
0097
0098 ### Related Statements
0099
0100 * [CREATE FUNCTION](sql-ref-syntax-ddl-create-function.html)
0101 * [DESCRIBE FUNCTION](sql-ref-syntax-aux-describe-function.html)
0102 * [SHOW FUNCTION](sql-ref-syntax-aux-show-functions.html)
