DROP FUNCTION
Description
The DROP FUNCTION statement drops a temporary or user defined function (UDF). An exception will
be thrown if the function does not exist.
Syntax
DROP [ TEMPORARY ] FUNCTION [ IF EXISTS ] function_name
Parameters
-
function_name
Specifies the name of an existing function. The function name may be optionally qualified with a database name.
Syntax:
[ database_name. ] function_name -
TEMPORARY
Should be used to delete the
TEMPORARYfunction. -
IF EXISTS
If specified, no exception is thrown when the function does not exist.
Examples
-- Create a permanent function `test_avg`
CREATE FUNCTION test_avg AS 'org.apache.hadoop.hive.ql.udf.generic.GenericUDAFAverage';
-- List user functions
SHOW USER FUNCTIONS;
+----------------+
| function|
+----------------+
|default.test_avg|
+----------------+
-- Create Temporary function `test_avg`
CREATE TEMPORARY FUNCTION test_avg AS
'org.apache.hadoop.hive.ql.udf.generic.GenericUDAFAverage';
-- List user functions
SHOW USER FUNCTIONS;
+----------------+
| function|
+----------------+
|default.test_avg|
| test_avg|
+----------------+
-- Drop Permanent function
DROP FUNCTION test_avg;
-- Try to drop Permanent function which is not present
DROP FUNCTION test_avg;
Error: Error running query:
org.apache.spark.sql.catalyst.analysis.NoSuchPermanentFunctionException:
Function 'default.test_avg' not found in database 'default'; (state=,code=0)
-- List the functions after dropping, it should list only temporary function
SHOW USER FUNCTIONS;
+--------+
|function|
+--------+
|test_avg|
+--------+
-- Drop Temporary function
DROP TEMPORARY FUNCTION IF EXISTS test_avg;