CREATE TABLE "filter_classes" (
  "usage" text,
  "class" text,
  "performance" text,
  "performance_test" text,
  "particulate_size_approaching_100pct_retention" text,
  "test_standard" text
);

Question: Which  Performance has a Test Standard of bs en779, and a Particulate size approaching 100% retention of >2µm, and a Class of f6?
SQL: SELECT "performance" FROM "filter_classes" WHERE "test_standard"='bs en779' AND "particulate_size_approaching_100pct_retention"='>2µm' AND "class"='f6';

Question: Which Performance has a Usage of hepa and a Class of h14?
SQL: SELECT "performance" FROM "filter_classes" WHERE "usage"='hepa' AND "class"='h14';

Question: Which Particulate size approaching 100% retention has a Usage of semi hepa and a Class of h12?
SQL: SELECT "particulate_size_approaching_100pct_retention" FROM "filter_classes" WHERE "usage"='semi hepa' AND "class"='h12';

Question: Which Test Standard has a Usage of secondary filters, and a Class of f5? Question 4
SQL: SELECT "test_standard" FROM "filter_classes" WHERE "usage"='secondary filters' AND "class"='f5';

Question: Which Performance has a Performance test of average value, and a Class of f6?
SQL: SELECT "performance" FROM "filter_classes" WHERE "performance_test"='average value' AND "class"='f6';

Question: Which Class has a Performance test of minimum value, and a Usage of semi hepa, and a Performance of 99.5%?
SQL: SELECT "class" FROM "filter_classes" WHERE "performance_test"='minimum value' AND "usage"='semi hepa' AND "performance"='99.5%';