What was the attendance on September 11, 1988?
CREATE TABLE table_name_21 (attendance INTEGER, date VARCHAR)
SELECT AVG(attendance) FROM table_name_21 WHERE date = "september 11, 1988"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_name_21 (attendance INTEGER, date VARCHAR) Question: What was the attendance on September 11, 1988? [/INST] SELECT AVG(attendance) FROM table_name_21 WHERE date = "september 11, 1988" </s>