SELECT country FROM stadium GROUP BY country HAVING count(*)  <=  3
Which country has at most 3 stadiums listed?
CREATE TABLE "swimmer" (
"ID" int,
"name" text,
"Nationality" text,
"meter_100" real,
"meter_200" text,
"meter_300" text,
"meter_400" text,
"meter_500" text,
"meter_600" text,
"meter_700" text,
"Time" text,
PRIMARY KEY ("ID")
);
CREATE TABLE "stadium" (
"ID" int,
"name" text,
"Capacity" int,
"City" text,
"Country" text,
"Opening_year" int,
PRIMARY KEY ("ID")
);
CREATE TABLE "event" (
"ID" int,
"Name" text,
"Stadium_ID" int,
"Year" text,
PRIMARY KEY ("ID"),
FOREIGN KEY (`Stadium_ID`) REFERENCES `stadium`(`ID`)
);
CREATE TABLE "record" (
"ID" int,
"Result" text,
"Swimmer_ID" int,
"Event_ID" int,
PRIMARY KEY ("Swimmer_ID","Event_ID"),
FOREIGN KEY (`Event_ID`) REFERENCES `event`(`ID`),
FOREIGN KEY (`Swimmer_ID`) REFERENCES `swimmer`(`ID`)
);
INSERT INTO  "swimmer" VALUES ("7","Przemysław Stańczyk","Poland","57.31","1:57.10","2:56.02","3:55.36","4:54.21","5:52.59","6:50.91","7:47.91");
INSERT INTO  "stadium" VALUES (1,"Nou Mestalla","75000","Valencia","Spain","2004");
INSERT INTO  "event" VALUES (1,"FINA",1,"2016");
INSERT INTO  "record" VALUES (1,"NC",1,1);