Question

嘿，我有一个按日期排序的查询，我希望日期与添加的时间顺序相同，以保持稳定的结果。

我有以下查询：

    (
SELECT  'album' AS RowType, id, DATE, title, time_added
FROM albums
WHERE is_temp =0
AND subject_id =  '3'
)
UNION ALL (

SELECT  'video' AS RowType, id, DATE, title, time_added
FROM videos
WHERE is_temp =0
AND subject_id =  '3'
)
UNION ALL (

SELECT  'story' AS RowType, id, DATE, title, time_added
FROM stories
WHERE is_temp =0
AND subject_id =  '3'
)
ORDER BY DATE, time_added

哪个效果很好但我不想要选择time_added列，因为我在结果集中不需要它。

我可以以某种方式实现这一目标吗？如果我删除time_added，查询将无法运行。

我找到了以下内容：

ORDER BY子句导致输出行被排序 ORDER BY的参数是一个用作表达式的表达式列表排序的关键。表达式不必是结果的一部分对于一个简单的SELECT，但在复合SELECT中每个排序表达式必须与其中一个结果列完全匹配。每种排序表达都可以可选地后跟一个COLLATE关键字和一个名称用于订购文本和/或关键字ASC或DESC的整理功能指定排序顺序。

我无法决定是否意味着它是不可能的，或者我应该更加努力。

Answer 1

试试这个

SELECT RowType
    , id
    , DATE
    , title
FROM 
(
    SELECT 'album' AS RowType , id , DATE , title , time_added
    FROM albums
    WHERE is_temp = 0 AND subject_id = '3'

    UNION ALL

    SELECT 'video' AS RowType , id , DATE , title , time_added
    FROM videos
    WHERE is_temp = 0 AND subject_id = '3'

    UNION ALL

    SELECT 'story' AS RowType , id , DATE , title , time_added
    FROM stories
    WHERE is_temp = 0 AND subject_id = '3'

) s
ORDER BY DATE , time_added

通过联合的未选择列排序

1 个答案: