what is the earliest began when the court surface is clay in hamburg?
CREATE TABLE table_name_21 (began INTEGER, court_surface VARCHAR, location VARCHAR)
SELECT MIN(began) FROM table_name_21 WHERE court_surface = "clay" AND location = "hamburg"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_name_21 (began INTEGER, court_surface VARCHAR, location VARCHAR) Question: what is the earliest began when the court surface is clay in hamburg? [/INST] SELECT MIN(began) FROM table_name_21 WHERE court_surface = "clay" AND location = "hamburg" </s>