PostgreSQL no permite mezclar instrucciones UPDATE y DELETE como subconsulta.
Puede usar una estrategia un poco diferente:CTE actualizable
postgres=# WITH t1 AS (DELETE FROM foo RETURNING *),
t2 AS (INSERT INTO deleted
SELECT * FROM t1 RETURNING *)
SELECT max(a) FROM t2;
entonces
postgres=# CREATE TABLE comment(id int, score int);
CREATE TABLE
postgres=# CREATE TABLE history(id int, comment_id int, vote int);
CREATE TABLE
postgres=# INSERT INTO comment values(1,10);
INSERT 0 1
postgres=# INSERT INTO comment values(2,20);
INSERT 0 1
postgres=# INSERT INTO history values(1,1,5);
INSERT 0 1
postgres=# WITH t1 AS (DELETE FROM history
WHERE id=1
RETURNING comment_id, vote)
UPDATE comment SET score=score-t1.vote
FROM t1
WHERE t1.comment_id=comment.id;
UPDATE 1
postgres=# select * from comment;
id | score
----+-------
2 | 20
1 | 5
(2 rows)
Atención:Requiere 9.1 o más reciente
