CREATE TABLE Office_locations (building_id VARCHAR, company_id VARCHAR)
CREATE TABLE buildings (name VARCHAR, id VARCHAR)
CREATE TABLE Companies (id VARCHAR)

Show the name of the building that has the most company offices.
SELECT T2.name FROM Office_locations AS T1 JOIN buildings AS T2 ON T1.building_id = T2.id JOIN Companies AS T3 ON T1.company_id = T3.id GROUP BY T1.building_id ORDER BY COUNT(*) DESC LIMIT 1
SELECT "T2"."name" FROM "Office_locations" AS "T1" JOIN "buildings" AS "T2" ON "T1"."building_id" = "T2"."id" JOIN "Companies" AS "T3" ON "T1"."company_id" = "T3"."id" GROUP BY "T1"."building_id" ORDER BY COUNT(*) DESC NULLS LAST LIMIT 1