sql - 选择主表中没有子表连接的行

Question

我有两个表：结果（主）和确认（子）：

CREATE TABLE result
(
  result_id serial NOT NULL
  CONSTRAINT result_pkey PRIMARY KEY (result_id)
)

CREATE TABLE confirmation
(
  confirmation_id serial NOT NULL,
  result_id integer
  CONSTRAINT confirmation_pkey PRIMARY KEY (confirmation_id),
  CONSTRAINT confirmation_result_id_fkey FOREIGN KEY (result_id)
      REFERENCES result (result_id) MATCH SIMPLE
      ON UPDATE NO ACTION ON DELETE NO ACTION
)

我能够找到所有得到确认的结果：

SELECT 
result.result_id,
confirmation.confirmation_id
FROM Result
JOIN confirmation ON confirmation.result_id = result.result_id

但我需要它，反之亦然 - 所有结果仍然没有一个确认。

Answer 1

SELECT * FROM result WHERE NOT EXISTS
(SELECT 1 FROM confirmation WHERE confirmation.result_id = result.result_id)