What is the average number of partners for the firm with a rank under 71, other over 77, and largest city of Philadelphia?
CREATE TABLE "see_also" (
  "rank" real,
  "largest_u_s_city" text,
  "total" real,
  "partners" real,
  "other" real
);
SELECT AVG("partners") FROM "see_also" WHERE "rank"<71 AND "largest_u_s_city"='philadelphia' AND "other">77;