MySQL FULL JOIN? [英] MySQL FULL JOIN?
本文介绍了MySQL FULL JOIN?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
以下是我的查询,我想要下面给出的结果.我该如何在mysql中做到这一点?
Following are my query and I want the result as given below. How can I do this in mysql ?
SELECT Persons.LastName, Persons.FirstName, Orders.OrderNo
FROM Persons
FULL JOIN Orders
ON Persons.P_Id=Orders.P_Id
ORDER BY Persons.LastName
结果集应如下所示:
LastName FirstName OrderNo
Hansen Ola 22456
Hansen Ola 24562
Pettersen Kari 77895
Pettersen Kari 44678
Svendson Tove
34764
推荐答案
MySQL缺乏对FULL OUTER JOIN的支持.
MySQL lacks support for FULL OUTER JOIN.
因此,如果您想在MySQL上模拟完全连接,请查看此处.
So if you want to emulate a Full join on MySQL take a look here .
通常建议的解决方法如下:
A commonly suggested workaround looks like this:
SELECT t_13.value AS val13, t_17.value AS val17
FROM t_13
LEFT JOIN
t_17
ON t_13.value = t_17.value
UNION ALL
SELECT t_13.value AS val13, t_17.value AS val17
FROM t_13
RIGHT JOIN
t_17
ON t_13.value = t_17.value
WHERE t_13.value IS NULL
ORDER BY
COALESCE(val13, val17)
LIMIT 30
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