How many Mountains Classifications were in the race with Mike Northey as Youth Classification?
CREATE TABLE table_23157997_13 (mountains_classification VARCHAR, youth_classification VARCHAR)
SELECT COUNT(mountains_classification) FROM table_23157997_13 WHERE youth_classification = "Mike Northey"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_23157997_13 (mountains_classification VARCHAR, youth_classification VARCHAR) Question: How many Mountains Classifications were in the race with Mike Northey as Youth Classification? [/INST] SELECT COUNT(mountains_classification) FROM table_23157997_13 WHERE youth_classification = "Mike Northey" </s>