查询在psql shell中返回结果，但不返回Django

Question

我尝试使用以下架构查询GeoIP数据库：

CREATE TABLE api_geoiprecord
(
    start_ip inet PRIMARY KEY NOT NULL,
    end_ip inet NOT NULL,
    region VARCHAR(2),
    country VARCHAR(2),
    city VARCHAR(50),
    postal_code VARCHAR(50),
    latitude DOUBLE PRECISION,
    longitude DOUBLE PRECISION,
    dma_code INT,
    area_code INT
);

当我在psql中运行此查询时，我得到了结果：

-- Test address, belongs to Yahoo!
SELECT city, country from api_geoiprecord
WHERE inet '68.180.194.242' BETWEEN start_ip AND end_ip
LIMIT 1;

   city    | country
-----------+---------
 Sunnyvale | CA
(1 row)

当我在Django中运行时，我什么都没得到：

def get_location(ip) -> None:
    cur = connection.cursor()
    cur.execute(
        """SELECT city, country FROM api_geoiprecord
           WHERE inet %s BETWEEN start_ip AND end_ip
           LIMIT 1;""",
        (ip, )
    )
    return cur.fetchone()

有什么想法？