Postgres upsert: distinguish between new and updated rows [duplicate]

问题

This question already has an answer here:

How can I get the INSERTED and UPDATED rows for an UPSERT operation in postgres (1 answer)

Closed 8 days ago.

I'm thinking of using PostgreSQL INSERT .. ON CONFLICT UPDATE functionality. Ideally I would be able to distinguish between which rows were successful inserted and which were updated. Is there a way to do it?

回答1:

You need an additional auxiliary column for this (updated in the example).

create table test (id int primary key, str text, updated boolean);
insert into test values (1, 'old', false);

insert into test values
    (1, 'new 1', false),
    (2, 'new 2', false)
on conflict (id) do
update set 
    str = excluded.str, updated = true
returning *;

 id |  str  | updated 
----+-------+---------
  1 | new 1 | t
  2 | new 2 | f
(2 rows)

回答2:

There is a way without adding a column to your table:

CREATE TABLE tbl(id int PRIMARY KEY, col int);
INSERT INTO tbl VALUES (1, 1);

INSERT INTO tbl(id, col)
VALUES (1,11), (2,22)
ON     CONFLICT (id) DO UPDATE
SET    col = EXCLUDED.col
RETURNING *, (xmax = 0) AS inserted;

Explanation:

• Detect if the row was updated or inserted

来源：https://stackoverflow.com/questions/38613887/postgres-upsert-distinguish-between-new-and-updated-rows