我写成这两样为什么返回的结果不一样呢？

[HappyCode1000]

SELECT pub_name
FROM publishers
WHERE NOT EXISTS
(SELECT *
FROM titles
WHERE pub_id = publishers.pub_id
AND type = 'business')


SELECT pub_name
FROM publishers
WHERE NOT EXISTS
(SELECT *
FROM titles t inner join publishers p on t.pub_id=p.pub_id
WHERE type = 'business')


查询语句中 not exist里的条件 我写成这两样为什么返回的结果不一样呢？
这两个难道不一样吗？

WHERE pub_id = publishers.pub_id 和 titles t inner join publishers p on t.pub_id=p.pub_id 一样呀？

[HappyCode1000]

还是不是很明白，能否再详细些呢？多谢!

[luoluo4529]

谁能告诉我为什么(SELECT *
FROM titles
WHERE pub_id = publishers.pub_id
AND type = 'business')
执行不了

[eru]

当然不一样
(SELECT *
FROM titles t inner join publishers p on t.pub_id=p.pub_id
WHERE type = 'business')
要么存在要么不存在，对外层查询的结果要么是全部，要么是没有
而
(SELECT *
FROM titles
WHERE pub_id = publishers.pub_id
AND type = 'business')
要对publishers中的每条记录进行判断

[LoveSQL]

楼上分析的有道理！