Question

我有这个查询结果，我希望将每个ID的第二行添加为

SELECT m.post_id,m.meta_value,p.post_title 
from events_posts p
inner join events_postmeta m 
on p.ID=m.post_id and p.post_type='event' and (p.post_status='publish' or p.post_status='recurring') 
and(m.meta_key='address' or m.meta_key='st_date')
order by m.post_id
 column.

现在结果：

post_id meta_value  post_title
15  Carolina Beach Road, Wilmington, NC, United States  An Art Exhibition
15  2014-02-03  An Art Exhibition
19  Dakota Street, Winnipeg, MB, Canada Weekly Karate Classes
19  2014-02-06  Weekly Karate Classes
23  Alaskan Way, Seattle, WA, United State  Christmas Carnival
23  2014-02-03  Christmas Carnival

我希望它是

post_id | meta_value| post_title

15  | Carolina Beach Road, Wilmington, NC, United States    | An Art Exhibition   | 2014-02-03  
19  |Dakota Street, Winnipeg, MB, Canada    |Weekly Karate Classes |2014-02-06   
23  |Alaskan Way, Seattle, WA, United State |Christmas Carnival |2014-02-03

Answer 1

您实际上不尝试将行转换为列。您正尝试将查询的两行合并为一行。通过两次加入events_postmeta应该可以实现这种行为。

SELECT p.ID, m1.meta_value as event_address, m2.meta_value as event_date, p.post_title 
from events_posts p
inner join events_postmeta m1
on p.ID=m1.post_id and p.post_type='event' and (p.post_status='publish' or p.post_status='recurring') 
and m1.meta_key='address'
inner join events_postmeta m2
on p.ID=m2.post_id and p.post_type='event' and (p.post_status='publish' or p.post_status='recurring') 
and m2.meta_key='st_date'
order by p.ID

这样m1 - join将地址添加为列，m2 - join添加日期。我无法测试这个，但我很确定它的工作原理（模拟一些输入语法错误）。

MySQL行作为列

1 个答案: