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

Question: What is the result for salmonella spp. if you use citrate?
SQL: SELECT COUNT("citrate") FROM "usage" WHERE "species"='Salmonella spp.';

Question: Which species show a negative result with both voges-proskauer and indole?
SQL: SELECT "species" FROM "usage" WHERE "voges_proskauer"='Negative' AND "indole"='Negative';

Question: What are the results for testing the species with voges-proskauer when citrate yields a positive result?
SQL: SELECT "voges_proskauer" FROM "usage" WHERE "citrate"='Positive';

Question: What is the result of proteus mirabilis tested with indole?
SQL: SELECT "indole" FROM "usage" WHERE "species"='Proteus mirabilis';