# Calling an External Function for Azure¶

This topic describes how to call an external function:

An external function is called like any other UDF (user-defined function). (And, like any other UDF, an external function is called the same way regardless of platform.)

1. If you have not already done so, make sure that your session is using the database and schema that contain the function.

(External functions are database objects; when you call the function, the database and schema containing the function must be in use in your session, or you must specify the fully-qualified name of the function.)

USE DATABASE <database_name>;
USE SCHEMA <schema_name>;

2. If appropriate, and if you have not already done so, grant USAGE privilege on the external function to one or more Snowflake roles that need to call the external function.

(A role must have USAGE or OWNERSHIP privileges on an external function to call it.)

GRANT USAGE ON FUNCTION <external_function_name>(<parameter_data_type>) TO <role_name>;


For example:

GRANT USAGE ON FUNCTION echo(INTEGER, VARCHAR) TO analyst_role;

3. Using an appropriate role, call your external function as part of an SQL statement. If you created one of the sample external functions supplied by Snowflake, you can call the function as shown below:

SELECT echo(42, 'Adams');


If you used a function name other than echo, then replace echo with the actual function name.

The returned value should be similar to:

[0, 42, "Adams"]


Where:

• 0 is the row number of the returned value.

• 42, "Adams" is the returned value.

Note

Although an external function can usually be called like other UDFs, there are a handful of exceptions. For details, see Execution-time Limitations and Issues.