what rank has viewers at 6.45?
CREATE TABLE table_15681686_4 (rank__week_ VARCHAR, viewers__millions_ VARCHAR)
SELECT rank__week_ FROM table_15681686_4 WHERE viewers__millions_ = "6.45"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_15681686_4 (rank__week_ VARCHAR, viewers__millions_ VARCHAR) Question: what rank has viewers at 6.45? [/INST] SELECT rank__week_ FROM table_15681686_4 WHERE viewers__millions_ = "6.45" </s>