When was the Hamaoka-4 unit commercial operation date?
CREATE TABLE table_name_42 (commercial_operation VARCHAR, unit VARCHAR)
SELECT commercial_operation FROM table_name_42 WHERE unit = "hamaoka-4"
### Context: CREATE TABLE table_name_42 (commercial_operation VARCHAR, unit VARCHAR) ### Question: When was the Hamaoka-4 unit commercial operation date? ### Answer: SELECT commercial_operation FROM table_name_42 WHERE unit = "hamaoka-4"