sql - PostgreSQL:如果不存在则插入，如果存在则返回ID

Question

如果没有 IP 地址，以下查询将插入 IP 地址并返回 ID。

WITH variables AS (
  SELECT '1.1.1.2'::inet AS ip
)
INSERT INTO globals.ips (ip)
SELECT v.ip
FROM variables AS v
WHERE NOT EXISTS (
    SELECT i.global_ip_id 
    FROM globals.ips AS i 
    WHERE i.ip = v.ip
)
RETURNING global_ip_id

但是，当该值已存在于数据库中时，它不会返回 ID。

当值已经存在时，如何获取 ID？

---

我正在运行 PostgreSQL 12。

Answer 1

WITH variables AS (
  SELECT '1.1.1.2'::inet AS ip
), wt0 as (
INSERT INTO globals.ips (ip)
SELECT v.ip
FROM variables AS v
WHERE NOT EXISTS (
    SELECT i.global_ip_id 
    FROM globals.ips AS i 
    WHERE i.ip = v.ip
)
RETURNING global_ip_id
)
SELECT global_ip_id FROM wt0
UNION
SELECT id FROM globals.ips WHERE ip = 'SOMETHING';