Question

好的，假设我有以下表格：

配方

id (pk)
name
added
modified

recipe_versions

id (pk)
recipe_id (fk to recipes.id)
version
content
added

我想要的是一个查询，它抓取最新的recipe_versions.added数据，然后加入基础recipe数据。然后按recipes.added ASC对所有结果进行排序我有以下内容，但是group by，没有选择最新的recipe_versions行，似乎是选择第一行。

SELECT r.`id`,
      r.name,
      rv.version,
      rv.content,
      r.added,
      r.modified,
 FROM recipes r,
      recipe_versions rv
WHERE r.`id` = rv.recipe
GROUP BY rv.recipe
HAVING max(rv.added) 
ORDER BY r.added ASC

Answer 1

使用此解决方案：

SELECT
    c.*, b.*
FROM
    (
        SELECT recipe_id, MAX(added) AS mostrecent
        FROM recipe_versions
        GROUP BY recipe_id
    ) a
INNER JOIN
    recipe_versions b ON 
        a.recipe_id = b.recipe_id AND
        a.mostrecent = b.added
INNER JOIN
    recipes c ON a.recipe_id = c.id
ORDER BY
    c.added

MySQL Group BY，有，按查询排序

1 个答案: