Question

我需要一个日期时间字段的MySQL条件ORDER BY语句。我有一个包含帖子的表格，我想通过以下方式订购：所有将来的帖子应该订购 ASC 以及所有历史帖子已订购的 DESC 即可。例如：

post_status     post_date     post_title
===========     =========     ==========
future          2012-10-01    Title 1
future          2012-12-01    Title 2
publish         2012-05-01    Title 3
publish         2012-01-01    Title 4

我需要类似于以下SQL的内容......

SELECT post_status, post_date, post_title FROM wp_posts
WHERE post_status IN ('future', 'publish')
ORDER BY post_status ASC,
 CASE post_status 
  WHEN 'future' THEN 'post_date ASC'
  ELSE 'post_date DESC'
 END;

有关如何执行此操作的任何提示？谢谢！

Answer 1

试试这个：

ORDER BY post_status ASC,
CASE post_status WHEN 'future' THEN POST_DATE END ASC,
CASE WHEN post_status <> 'future' THEN post_date END DESC

Answer 2

这样的事情怎么样？选择两次并结合结果。

Select * from (SELECT post_status, post_date, post_title 
FROM wp_posts WHERE post_status IN ('future') 
ORDER BY post_status ASC  ) alias1  
UNION
Select * from (SELECT post_status, post_date, post_title 
FROM wp_posts WHERE post_status IN ('publish') 
ORDER BY post_status DESC ) alias2

Answer 3

试试这个 -

SELECT
  post_status, post_date, post_title
FROM
  wp_posts
WHERE
  post_status IN ('future', 'publish')
ORDER BY
  IF(post_status = 'future', 0, 1),
  IF(post_status = 'future', TO_DAYS(post_date), TO_DAYS(post_date) * -1);

Answer 4

我会使用union all，order by中的技巧无法使用索引而且速度较慢。

SELECT * FROM
((SELECT
  1 AS a, @rownum:=@rownum+1 B, post_status, post_date, post_title
FROM
  wp_posts, (SELECT @rownum:=0) r 
WHERE
  post_status='publish'
ORDER BY
  post_date DESC)
UNION ALL
(SELECT
  2 AS a,  @rownum:=@rownum+1 B, post_status, post_date, post_title
FROM
  wp_posts, (SELECT @rownum:=0) r2
WHERE
  post_status='future'
ORDER BY
  post_date)) ORDER BY A,B;

MySQL条件ORDER BY ASC / DESC用于日期列

4 个答案: