What was the original air date for the episode with 3.90 u.s. viewers (millions)?
CREATE TABLE table_12722302_2 (original_air_date VARCHAR, us_viewers__million_ VARCHAR)
SELECT original_air_date FROM table_12722302_2 WHERE us_viewers__million_ = "3.90"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_12722302_2 (original_air_date VARCHAR, us_viewers__million_ VARCHAR) Question: What was the original air date for the episode with 3.90 u.s. viewers (millions)? [/INST] SELECT original_air_date FROM table_12722302_2 WHERE us_viewers__million_ = "3.90" </s>