CREATE TABLE "roller_coasters" (
  "name" text,
  "style" text,
  "opened" real,
  "manufacturer" text,
  "themed_area" text
);

Question: Which average Opened has a Manufacturer of vekoma?
SQL: SELECT AVG("opened") FROM "roller_coasters" WHERE "manufacturer"='vekoma';

Question: Which Opened is the highest one that has a Themed Area of aerial park, and a Manufacturer of zamperla?
SQL: SELECT MAX("opened") FROM "roller_coasters" WHERE "themed_area"='aerial park' AND "manufacturer"='zamperla';

Question: Which Themed Area has a Name of troublesome trucks runaway coaster?
SQL: SELECT "themed_area" FROM "roller_coasters" WHERE "name"='troublesome trucks runaway coaster';

Question: Which Manufacturer has a Style of steel sit down, and an Opened larger than 2008?
SQL: SELECT "manufacturer" FROM "roller_coasters" WHERE "style"='steel sit down' AND "opened">2008;