Table: emulator_list
Columns: name
current_version
system
platform
license

Question: What platform is nds4droid on for the nintendo ds?
SQL: SELECT "platform" FROM emulator_list WHERE "system" = 'nintendo ds' AND "name" = 'nds4droid'

Question: Who has a license of proprietary (available on inquiry)?
SQL: SELECT "name" FROM emulator_list WHERE "license" = 'proprietary (available on inquiry)'

Question: What platform is nds4droid on for the nintendo ds with a license of gpl v2?
SQL: SELECT "platform" FROM emulator_list WHERE "system" = 'nintendo ds' AND "license" = 'gpl v2' AND "name" = 'nds4droid'

Question: What system has a current version of 1.4e?
SQL: SELECT "system" FROM emulator_list WHERE "current_version" = '1.4e'

Question: Who has a licence of gpl v2 and a current version of 0.9.9?
SQL: SELECT "name" FROM emulator_list WHERE "license" = 'gpl v2' AND "current_version" = '0.9.9'