CREATE TABLE "references" (
  "type" text,
  "registration" text,
  "design" text,
  "construction" text,
  "service" text,
  "construction_date" text,
  "conformity_to_original_design" text,
  "interest" text,
  "number_existing_in_switzerland" text,
  "number_existing_worldwide" text,
  "status" text
);

Question: What are all types where registration is HB-OPU?
SQL: SELECT "type" FROM "references" WHERE "registration"='HB-OPU';

Question: What is every registration for the type of T 6 G?
SQL: SELECT "registration" FROM "references" WHERE "type"='T 6 G';

Question: What is every construction date for the registration of HB-HOS?
SQL: SELECT "construction_date" FROM "references" WHERE "registration"='HB-HOS';

Question: What is every conformity to original design if the construction date is after 1945 and registration is HB-SAE?
SQL: SELECT "conformity_to_original_design" FROM "references" WHERE "construction_date"='After 1945' AND "registration"='HB-SAE';

Question: What is every conformity to original design if registration is HB-DAI?
SQL: SELECT "conformity_to_original_design" FROM "references" WHERE "registration"='HB-DAI';