What is the sum of launches with Long March 3 and 0 failures?
CREATE TABLE "by_type" (
  "rocket" text,
  "country" text,
  "family" text,
  "launches" real,
  "successes" real,
  "failures" real,
  "partial_failures" real
);
SELECT SUM("launches") FROM "by_type" WHERE "rocket"='long march 3' AND "failures">0;