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

  1. 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 TEMPORARY function.

  • IF EXISTS

    If specified, no exception is thrown when the function does not exist.

Examples

  1. -- Create a permanent function `test_avg`
  2. CREATE FUNCTION test_avg AS 'org.apache.hadoop.hive.ql.udf.generic.GenericUDAFAverage';
  4. -- List user functions
  5. SHOW USER FUNCTIONS;
  6. +----------------+
  7. |        function|
  8. +----------------+
  9. |default.test_avg|
  10. +----------------+
  12. -- Create Temporary function `test_avg`
  13. CREATE TEMPORARY FUNCTION test_avg AS
  14.     'org.apache.hadoop.hive.ql.udf.generic.GenericUDAFAverage';
  16. -- List user functions
  17. SHOW USER FUNCTIONS;
  18. +----------------+
  19. |        function|
  20. +----------------+
  21. |default.test_avg|
  22. |        test_avg|
  23. +----------------+
  25. -- Drop Permanent function
  26. DROP FUNCTION test_avg;
  28. -- Try to drop Permanent function which is not present
  29. DROP FUNCTION test_avg;
  30. Error: Error running query:
  31. org.apache.spark.sql.catalyst.analysis.NoSuchPermanentFunctionException:
  32. Function 'default.test_avg' not found in database 'default'; (state=,code=0)
  34. -- List the functions after dropping, it should list only temporary function
  35. SHOW USER FUNCTIONS;
  36. +--------+
  37. |function|
  38. +--------+
  39. |test_avg|
  40. +--------+
  42. -- Drop Temporary function
  43. DROP TEMPORARY FUNCTION IF EXISTS test_avg;