Table: hms_bluebell
Columns: name
class
navy
date_joined
date_departed

Question: What's the departed date for Grimsby Class Sloop?
SQL: SELECT "date_departed" FROM hms_bluebell WHERE "class" = 'grimsby class sloop'

Question: What's the departed date that the HMS Leith of the Royal Navy?
SQL: SELECT "date_departed" FROM hms_bluebell WHERE "navy" = 'royal navy' AND "name" = 'hms leith'

Question: What's the class of the HMS Fowey?
SQL: SELECT "class" FROM hms_bluebell WHERE "name" = 'hms fowey'

Question: What's the class of the HMS Heartsease?
SQL: SELECT "class" FROM hms_bluebell WHERE "name" = 'hms heartsease'