Function operations

CREATE FUNCTION <function_name> AS <package_to_class> USING <resource_list>;

• function_name: the name of the user-defined function (UDF) to create. Function names must be unique. Each function name can be used only once.
  Note Generally, UDFs cannot overwrite system built-in functions. Only the project owner can overwrite built-in functions. If you use a UDF that overwrites a built-in function, warning information is included in the Summary parameter after the SQL statement is executed.
• package_to_class: the package name. You must enclose the package name within single quotation marks (' ').
  • For a Java UDF, specify this name as a fully qualified class name from the top-level package name to the UDF class name.
  • For a Python UDF, specify this name in the format of Python_script_name.class_name.
• resource_list: the resource list that is used by the UDF.
  • This resource list must include the resource that contains the UDF code. Make sure that this resource has been uploaded to MaxCompute.
  • If the code reads resource files by using the Distributed Cache API, this resource list must also contain the list of resource files that are read by the UDF.
  • The resource list consists of multiple resource names. Separate the resource names with commas (,) and enclose the resource list in single quotation marks (' ').
  • To specify the project that contains the resource, write the expression as <project_name>/resources/<resource_name>.

• Create the my_lower function. In this example, the Java UDF class org.alidata.odps.udf.examples.Lower is in my_lower.jar.

  CREATE FUNCTION my_lower AS 'org.alidata.odps.udf.examples.Lower' USING 'my_lower.jar';

• Create the my_lower function. In this example, the Python UDF class MyLower is in the pyudf_test.py script of the test_project project.

  create function my_lower as 'pyudf_test.MyLower' using 'test_project/resources/pyudf_test.py';

• Create the test_udtf function. In this example, the Java UDF class com.aliyun.odps.examples.udf.UDTFResource is in udtfexample1.jar. The function depends on the resource file file_resource.txt, the table resource table_resource1, and the archive resource test_archive.zip.

  create function test_udtf as 'com.aliyun.odps.examples.udf.UDTFResource' using 'udtfexample1.jar, file_resource.txt, table_resource1,test_archive.zip';

DROP FUNCTION <function_name>;

DROP FUNCTION my_lower;

DESC FUNCTION <function_name>;

• View all UDFs within the current project.

  LIST FUNCTIONS; 

• View all UDFs within a specified project.

  LIST FUNCTIONS -p project_name;