CREATE TABLE "current_network" (
  "line" text,
  "began_operation" real,
  "stations" real,
  "length_km" text,
  "terminals" text
);

Question: When is the earliest began operation with a length of sultan ismail and over 27 stations?
SQL: SELECT MIN("began_operation") FROM "current_network" WHERE "length_km"='sultan ismail' AND "stations">27;

Question: What is the average operation beginning with a length of ampang and over 27 stations?
SQL: SELECT AVG("began_operation") FROM "current_network" WHERE "length_km"='ampang' AND "stations">27;