CREATE TABLE "usage" (
  "species" text,
  "indole" text,
  "methyl_red" text,
  "voges_proskauer" text,
  "citrate" text
);

Question: Which species has a Voges-Proskauer reading of negative and an indole reading of negative?
SQL: SELECT "species" FROM "usage" WHERE "voges_proskauer"='negative' AND "indole"='negative';

Question: What is the Voges-Proskauer reading for proteus mirabilis?
SQL: SELECT "voges_proskauer" FROM "usage" WHERE "species"='proteus mirabilis';

Question: What is the methyl red reading for the species that tests positive for indole?
SQL: SELECT "methyl_red" FROM "usage" WHERE "indole"='positive';

Question: What is the methyl red reading for proteus mirabilis?
SQL: SELECT "methyl_red" FROM "usage" WHERE "species"='proteus mirabilis';