What trains have a category of express and a weekly frequency?
CREATE TABLE table_21716139_1 (train_name VARCHAR, category VARCHAR, frequency VARCHAR)
SELECT train_name FROM table_21716139_1 WHERE category = "Express" AND frequency = "Weekly"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_21716139_1 (train_name VARCHAR, category VARCHAR, frequency VARCHAR) Question: What trains have a category of express and a weekly frequency? [/INST] SELECT train_name FROM table_21716139_1 WHERE category = "Express" AND frequency = "Weekly" </s>