CREATE TABLE table_name_47 (particulate_size_approaching_100_percentage_retention VARCHAR, usage VARCHAR, class VARCHAR)

Which Particulate size approaching 100% retention has a Usage of semi hepa and a Class of h12?
SELECT particulate_size_approaching_100_percentage_retention FROM table_name_47 WHERE usage = "semi hepa" AND class = "h12"
SELECT "particulate_size_approaching_100_percentage_retention" FROM "table_name_47" WHERE "class" = "h12" AND "semi hepa" = "usage"