What is the production code of the episode written by Jack Carrerrow?
CREATE TABLE table_20967430_4 (prod_code VARCHAR, written_by VARCHAR)
SELECT prod_code FROM table_20967430_4 WHERE written_by = "Jack Carrerrow"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_20967430_4 (prod_code VARCHAR, written_by VARCHAR) Question: What is the production code of the episode written by Jack Carrerrow? [/INST] SELECT prod_code FROM table_20967430_4 WHERE written_by = "Jack Carrerrow" </s>