CREATE TABLE "pool_2" (
  "team" text,
  "tries_for" text,
  "tries_against" text,
  "try_diff" text,
  "points_for" text,
  "points_against" text,
  "points_diff" text
);

Question: What is Tries Against, when Points Against is 213?
SQL: SELECT "tries_against" FROM "pool_2" WHERE "points_against"='213';

Question: What is Tries Against, when Tries For is 21?
SQL: SELECT "tries_against" FROM "pool_2" WHERE "tries_for"='21';

Question: What is Try Diff, when Points Diff is +71?
SQL: SELECT "try_diff" FROM "pool_2" WHERE "points_diff"='+71';

Question: What is Try Diff, when Points Against is 213?
SQL: SELECT "try_diff" FROM "pool_2" WHERE "points_against"='213';

Question: What is Tries Against, when Try Diff is +15?
SQL: SELECT "tries_against" FROM "pool_2" WHERE "try_diff"='+15';