PostgreSQL 高级特性. FILTER RETURNING 特性

1.统计数量

Filter Where 方法:
SELECT
  COUNT(*) FILTER (WHERE LEVEL = 'VIP') AS vip_count,
  COUNT(*) FILTER (WHERE LEVEL = 'SVIP') AS vip_count
FROM
  end_customer

2.返回自增ID

INSERT INTO end_customer (LEVEL)
VALUES
('VIP') RETURNING ID

3.Level分组获取最新数据

SELECT DISTINCT ON
  (LEVEL) 
  id as 最新ID,
  LEVEL
FROM
  end_customer
ORDER BY
  LEVEL,
  id DESC

总结

记录一下.