CREATE TABLE table_1590967_7 (musical_guest__song_performed_ VARCHAR, guest_host VARCHAR)

What song was performed when Barbara Windsor was the guest host?
SELECT musical_guest__song_performed_ FROM table_1590967_7 WHERE guest_host = "Barbara Windsor"
SELECT "musical_guest__song_performed_" FROM "table_1590967_7" WHERE "Barbara Windsor" = "guest_host"