Table: navy_destroyers
Columns: ship
built_as
reclassified_as
class
commissioned_decommissioned
nvr_link

Question: Where the ship is Dahlgren what is the build as?
SQL: SELECT "built_as" FROM navy_destroyers WHERE "ship" = 'dahlgren'

Question: Where the NRV link is CGN38, what is the reclassified as?
SQL: SELECT "reclassified_as" FROM navy_destroyers WHERE "nvr_link" = 'cgn38'

Question: Where the built as is DLG-23, what is the class?
SQL: SELECT "class" FROM navy_destroyers WHERE "built_as" = 'dlg-23'