How many series numbers do the episodes originally aired on October 28, 1990?
CREATE TABLE table_2226817_6 (no_in_series VARCHAR, original_air_date VARCHAR)
SELECT COUNT(no_in_series) FROM table_2226817_6 WHERE original_air_date = "October 28, 1990"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_2226817_6 (no_in_series VARCHAR, original_air_date VARCHAR) Question: How many series numbers do the episodes originally aired on October 28, 1990? [/INST] SELECT COUNT(no_in_series) FROM table_2226817_6 WHERE original_air_date = "October 28, 1990" </s>