On what surface was the opponent Michael Berrer?
CREATE TABLE table_name_15 (surface VARCHAR, opponent VARCHAR)
SELECT surface FROM table_name_15 WHERE opponent = "michael berrer"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_name_15 (surface VARCHAR, opponent VARCHAR) Question: On what surface was the opponent Michael Berrer? [/INST] SELECT surface FROM table_name_15 WHERE opponent = "michael berrer" </s>