CREATE TABLE "under_construction" (
  "rank" real,
  "name" text,
  "span_metres" real,
  "span_feet" real,
  "material" text,
  "year_opened" real,
  "location" text,
  "country" text
);

Question: What is the sum of Year opened when steel was the material with a Span feet of 1476?
SQL: SELECT SUM("year_opened") FROM "under_construction" WHERE "material"='steel' AND "span_feet"=1476;

Question: What is the sum of Year opened when the span feet is more than 1247, and the spam metres is 384?
SQL: SELECT SUM("year_opened") FROM "under_construction" WHERE "span_feet">1247 AND "span_metres"=384;