SQL与GROUP BY和ORDER BY

Question

我想从一个表中显示帖子从另一个表中的某些元值分组，并按其他元值或帖子ID排序，如果选择“最近”的顺序。

我想出的最好的是：

SELECT `posts`.`id_post`, 
     m1.value AS REGIUNE, 
     m2.value AS JUDET, 
     m3.value AS LOCALITATE, 
     MAX(`posts`.`id_post`) AS ORDERBY 
FROM `posts` 
INNER JOIN `posts_meta` m1 
    ON(`posts`.`id_post`=m1.`id_post`) 
INNER JOIN `posts_meta` m2 
    ON(`posts`.`id_post`=m2.`id_post`) 
INNER JOIN `posts_meta` m3 
    ON(`posts`.`id_post`=m3.`id_post`) 
WHERE 
    `posts`.`type` = 'published' 
AND (m1.`meta` = 'regiune') 
AND (m2.`meta` = 'judet') 
AND (m3.`meta` = 'localitate') 
GROUP BY posts.id_post 
ORDER BY ORDERBY DESC 

但是，这仅如果我们不被任何meta值（m1.value，m2.value或m3.value）分组工作。

Answer 1

这一个应该工作...

SELECT `posts`.`id_post`, 
     m1.value AS REGIUNE, 
     m2.value AS JUDET, 
     m3.value AS LOCALITATE, 
     MAX(`posts`.`id_post`) AS ORDERBY 
FROM `posts` 
INNER JOIN `posts_meta` m1 
    ON(`posts`.`id_post`=m1.`id_post`) 
INNER JOIN `posts_meta` m2 
    ON(`posts`.`id_post`=m2.`id_post`) 
INNER JOIN `posts_meta` m3 
    ON(`posts`.`id_post`=m3.`id_post`) 
WHERE 
    `posts`.`type` = 'published' 
AND (m1.`meta` = 'regiune') 
AND (m2.`meta` = 'judet') 
AND (m3.`meta` = 'localitate') 
GROUP BY 1,2,3,4 
ORDER BY `posts`.`id_post` DESC