MySQL不支持INTERSECT和MINUS及其替代方法
2022-11-12 09:36:49
内容摘要
这篇文章主要为大家详细介绍了MySQL不支持INTERSECT和MINUS及其替代方法，具有一定的参考价值，可以用来参考一下。
对此感兴趣的朋友，看看idc笔记做的技术笔记！Doing INTERSECT
文章正文
这篇文章主要为大家详细介绍了MySQL不支持INTERSECT和MINUS及其替代方法，具有一定的参考价值，可以用来参考一下。
对此感兴趣的朋友，看看idc笔记做的技术笔记！
Doing INTERSECT and MINUS in MySQLDoing an INTERSECTAn INTERSECT is simply an inner join where we compare the tuples of one table with those of the other, and select those that appear in both while weeding out duplicates. So代码如下:
SELECT member_id, name FROM a
INTERSECT
SELECT member_id, name FROM b
can simply be rewritten to
代码如下:
SELECT a.member_id, a.name
FROM a INNER JOIN b
USING (member_id, name)
Performing a MINUSTo transform the statement
代码如下:
SELECT member_id, name FROM a
MINUS
SELECT member_id, name FROM b
into something that MySQL can process, we can utilize subqueries (available from MySQL 4.1 onward). The easy-to-understand transformation is:
代码如下:
SELECT DISTINCT member_id, name
FROM a
WHERE (member_id, name) NOT IN
(SELECT member_id, name FROM table2);
Of course, to any long-time MySQL user, this is immediately obvious as the classical use-left-join-to-find-what-isn't-in-the-other-table:
代码如下:
SELECT DISTINCT a.member_id, a.name
FROM a LEFT JOIN b USING (member_id, name)
WHERE b.member_id IS NULL
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代码注释
作者：喵哥笔记
