CREATE TABLE "defense" (
  "player" text,
  "tackles" real,
  "asst" real,
  "total_tk" real,
  "sack" real,
  "yards" real,
  "fum_r" real
);

Question: What is the total of yards when asst. is 19, totaltk is 60 and sack is more than 0?
SQL: SELECT SUM("yards") FROM "defense" WHERE "asst"=19 AND "total_tk"=60 AND "sack">0;

Question: what is the total sack for mike green when fumr is less than 0?
SQL: SELECT SUM("sack") FROM "defense" WHERE "player"='mike green' AND "fum_r"<0;

Question: what is the total sack when totaltk is 1 and asst. is more than 0?
SQL: SELECT SUM("sack") FROM "defense" WHERE "total_tk"=1 AND "asst">0;

Question: what is the total number of tackles when fumr is 0, totaltk is 54 and yards is less than 0?
SQL: SELECT COUNT("tackles") FROM "defense" WHERE "fum_r"=0 AND "total_tk"=54 AND "yards"<0;

Question: what is the sum of totaltk when yards is less than 0?
SQL: SELECT SUM("total_tk") FROM "defense" WHERE "yards"<0;