CREATE TABLE "defense" (
  "player" text,
  "tackles" real,
  "solo" real,
  "assisted" real,
  "sack" real,
  "yards" real,
  "td_s" real
);

Question: How many yards for the player with 20 solo tackles and under 0 TDs?
SQL: SELECT SUM("yards") FROM "defense" WHERE "solo"=20 AND "td_s"<0;

Question: How many yards for the player with 1 solo tackle and over 0 sacks?
SQL: SELECT MAX("yards") FROM "defense" WHERE "solo"=1 AND "sack">0;