Postgres UPSERT UPdate 使用行值

Question

如果我的table是这样的

CREATE TABLE public.temperatures (
  temperature_io_id        integer NOT NULL,
  temperature_station_id   integer NOT NULL,
  temperature_value        double precision NOT NULL,
  temperature_current_kw  double precision NOT NULL,
  temperature_value_added  integer DEFAULT 1,
  temperature_kw_year_1   double precision DEFAULT 0,
  /* Keys */
  CONSTRAINT temperatures_pkey
    PRIMARY KEY (temperature_io_id, temperature_station_id, temperature_value)
) WITH (
    OIDS = FALSE
  );

当存在 io_id、station_id 和温度的唯一组合时，我正在尝试向 table 添加值。如果这个组合已经存在，我想更新 kw 值并将 1 添加到 value_added 字段。这将用于在温度下保持运行 kw 的平均值。

INSERT INTO temperatures
(temperature_io_id, temperature_station_id, temperature_value, temperature_curr_kw)
VALUES
(20,30,40,10)
ON CONFLICT
(temperature_io_id, temperature_station_id, temperature_value)
DO UPDATE SET    
temperature_current_kwh = ((temperature_current_kw * temperature_value_added) + EXCLUDED.temperature_current_kw) / (temperature_value_added + 1),
                        temperature_value_added = temperature_value_added + 1;

我如何在执行更新时访问行中的值？当我尝试访问 temperature_current_kw?

时出现不明确的错误

Answer 1

使用 table 别名：

INSERT INTO temperatures as t
    (temperature_io_id, temperature_station_id, temperature_value, temperature_current_kw)
VALUES
    (20,30,40,10)
ON CONFLICT
    (temperature_io_id, temperature_station_id, temperature_value)
DO UPDATE SET    
    temperature_current_kw = ((t.temperature_current_kw * t.temperature_value_added) + EXCLUDED.temperature_current_kw) / (t.temperature_value_added + 1),
    temperature_value_added = t.temperature_value_added + 1;

如the documentation所述：

alias

A substitute name for table_name. When an alias is provided, it completely hides the actual name of the table. This is particularly useful when ON CONFLICT DO UPDATE targets a table named excluded, since that's also the name of the special table representing rows proposed for insertion.

Postgres UPSERT UPdate 使用行值

Postgres UPSERT UPdate using rows values

sql

postgresql

unique

upsert