CREATE TABLE "diesel_multiple_units" (
  "type" text,
  "numbers" text,
  "year_built" real,
  "quantity_built" text,
  "power_horsepower" real,
  "max_speed_km_h" real
);

Question: What is the max speed of the unit with an 8+4 quantity built before 1971?
SQL: SELECT SUM("max_speed_km_h") FROM "diesel_multiple_units" WHERE "quantity_built"='8+4' AND "year_built"<1971;

Question: What is the numbers of the thn unit with a power greater than 220?
SQL: SELECT "numbers" FROM "diesel_multiple_units" WHERE "power_horsepower">220 AND "type"='thn';

Question: What is the power of the unit built after 1995?
SQL: SELECT SUM("power_horsepower") FROM "diesel_multiple_units" WHERE "year_built">1995;