CREATE TABLE "player_selections" (
  "year" real,
  "pick" text,
  "player_name" text,
  "position" text,
  "college" text
);

Question: I want the sum of year for mark barron
SQL: SELECT SUM("year") FROM "player_selections" WHERE "player_name"='mark barron';

Question: Tell me the year for defensive tackle and college of lsu
SQL: SELECT "year" FROM "player_selections" WHERE "position"='defensive tackle' AND "college"='lsu';