CREATE TABLE "engine_num7002" (
  "class" text,
  "firebox" text,
  "cylinder_size" text,
  "valves" text,
  "valve_gear" text,
  "number_built" text,
  "years_built" text
);

Question: What was the cylinder size of this engine that was made with only 88 pieces?
SQL: SELECT "cylinder_size" FROM "engine_num7002" WHERE "number_built"='88';

Question: What was the engine class that was built on 1906-08?
SQL: SELECT "class" FROM "engine_num7002" WHERE "years_built"='1906-08';

Question: How many engines were built with a cylinder size of 20 ½” x 26”, firebox is belpaire and valve gear is from Stephenson?
SQL: SELECT "number_built" FROM "engine_num7002" WHERE "cylinder_size"='20 ½” x 26”' AND "firebox"='Belpaire' AND "valve_gear"='Stephenson';

Question: This engine with a cylinder size of 20 ½” x 26” and a firebox of radial-stay was built when?
SQL: SELECT "years_built" FROM "engine_num7002" WHERE "cylinder_size"='20 ½” x 26”' AND "firebox"='Radial-stay';

Question: How many types of valves were used on this engine that was built on 1902-05?
SQL: SELECT COUNT("valves") FROM "engine_num7002" WHERE "years_built"='1902-05';