具有多个唯一约束的Postgresql UPSERT

Question

我已经创建了一张表作为位置（世界上的城市）。

CREATE TABLE location (
    location_id BIGSERIAL PRIMARY KEY,
    location_name VARCHAR(100) NOT NULL,
    state_id INT,
    country_id INT NOT NULL,
    UNIQUE (location_name, state_id, country_id),
    FOREIGN KEY (state_id) REFERENCES state (state_id)
    ON UPDATE CASCADE ON DELETE CASCADE,
    FOREIGN KEY (country_id) REFERENCES country (country_id)
    ON UPDATE CASCADE ON DELETE CASCADE
    );

CREATE UNIQUE INDEX loc_1_uni_idx ON location (location_name, country_id)
    WHERE state_id IS NULL;

此表具有两个唯一性检查：如果state_id为null，则location_name + country_id；如果state_id有值，则location_name + state_id + country_id。

当前，我想对该表进行upsert。对于上述两种情况，我都可以执行冲突处理：

INSERT INTO location(location_name, state_id, country_id) VALUES %s 
ON CONFLICT (location_name, state_id, country_id) 
DO UPDATE 
   SET country_id = EXCLUDED.country_id 
RETURNING location_id;

INSERT INTO location(location_name, state_id, country_id) VALUES %s 
ON CONFLICT (location_name, country_id) 
   WHERE state_id IS NULL 
DO UPDATE SET country_id = EXCLUDED.country_id 
RETURNING location_id;

但是，由于state_id可能存在或可能不存在，我该如何执行一次upsert来满足这两种情况？谢谢。