How many original air dates were there for episodes with a production code of 4398016?
CREATE TABLE table_21164557_1 (original_air_date VARCHAR, production_code VARCHAR)
SELECT COUNT(original_air_date) FROM table_21164557_1 WHERE production_code = 4398016
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_21164557_1 (original_air_date VARCHAR, production_code VARCHAR) Question: How many original air dates were there for episodes with a production code of 4398016? [/INST] SELECT COUNT(original_air_date) FROM table_21164557_1 WHERE production_code = 4398016 </s>