sqlite按随机组排序

Question

我有一张包含曲目和专辑列的歌曲表，我想以随机的专辑顺序获取它们。即，在每张专辑中，歌曲将被分类，但专辑将以随机顺序排列。

例如，如果表格为：

-----------------
| track | album |
-----------------
| 1     | a     |
| 2     | a     |
| 3     | a     |
| 1     | b     |
| 2     | b     |
| 1     | c     |
| 2     | c     |
-----------------

比可能的输出

-----------------
| track | album |
-----------------
| 1     | b     |
| 2     | b     |
| 1     | c     |
| 2     | c     |
| 1     | a     |
| 2     | a     |
| 3     | a     |
-----------------

可以使用单个sqlite查询吗？

Answer 1

首先，您需要随机订购相册，然后选择曲目。

with tt as (
  select distinct album from t order by random()
)
select t.track, tt.album 
from tt left join t on t.album = tt.album
order by tt.rowid, t.track
;

请参阅Sqlfiddle

Answer 2

为了达到预期的顺序，我必须在MrSimpleMind的答案中添加一个订单：

WITH albums AS (SELECT DISTINCT album FROM songs ORDER BY RANDOM()) 
SELECT songs.* FROM albums
LEFT JOIN songs
ON songs.album = albums.album
ORDER BY albums.rowid, songs.track