Question

我的第一个查询

SELECT ID FROM wp_posts 
WHERE post_type = 'post' AND post_status = 'publish' 
AND ID IN (Select object_id FROM wp_term_relationships, wp_terms
           WHERE wp_term_relationships.term_taxonomy_id =18) 
ORDER BY post_date DESC

生成结果

 31 and 28

和我的第二个查询

SELECT ID FROM wp_posts 
WHERE post_type = 'post' AND post_status = 'publish' 
AND ID IN (Select object_id FROM wp_term_relationships, wp_terms 
           WHERE wp_term_relationships.term_taxonomy_id =8) 
ORDER BY post_date DESC

将产生

31 and 33

我只需要获得两个查询result.ie，31的交集。我们怎样才能使用mysql

Answer 1

一种简单的方法是：

SELECT FROM (that entire first query) WHERE ID IN (that entire second query)

我对它的效率没有任何承诺......

Answer 2

交叉只不过是一个内连接，实际上是：

select
    a.ID as ID
from
    (SELECT ID FROM wp_posts WHERE post_type = 'post' AND post_status = 'publish' AND ID IN (Select object_id FROM wp_term_relationships, wp_terms WHERE wp_term_relationships.term_taxonomy_id =8 or wp_term_relationships.term_taxonomy_id =18)) as a,
    (SELECT ID FROM wp_posts WHERE post_type = 'post' AND post_status = 'publish' AND ID IN (Select object_id FROM wp_term_relationships, wp_terms WHERE wp_term_relationships.term_taxonomy_id =18 or wp_term_relationships.term_taxonomy_id =18)) as b
where
    a.ID=b.ID

从我的头顶。我只是复制＆amp;粘贴你的疑问，顺便说一句。

Answer 3

您的查询不明确。看看第二个查询。你有以下

wp_term_relationships.term_taxonomy_id =18   OR
wp_term_relationships.term_taxonomy_id =18

Answer 4

hmmm intersection - 尝试内连接：P

mysql中的交集

4 个答案: