![](/img/trans.png)
[英]MySQL - how do I do an outer join where either side is optional - left and right outer join
[英]How can I add a where clause to a right outer join union left outer join?
我正在使用以下 SQL,並且想知道如何以及在何處放置 where 子句。 例如,我可以將所有結果帶到 id=2 的地方?
SELECT *
FROM public_tips
LEFT OUTER JOIN likes
USING (id)
UNION
SELECT *
FROM likes
RIGHT OUTER JOIN public_tips
USING (id)
我努力了
SELECT *
FROM public_tips WHERE id=2
LEFT OUTER JOIN likes
USING (id)
UNION
SELECT *
FROM likes WHERE id=2
RIGHT OUTER JOIN public_tips
USING (id)
但我收到一個語法錯誤!
where
子句在from
子句之后, join
子句是from
子句的一部分:
SELECT *
FROM public_tips
LEFT OUTER JOIN likes
USING (id)
WHERE public_tips.id=2
UNION
SELECT *
FROM likes
RIGHT OUTER JOIN public_tips
USING (id)
WHERE public_tips.id=2
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.