MySQL-获取列的所有唯一值，检查是否具有特定值

Question

First off - apologies for the poor title, I have no idea how to describe it in a one-liner. I have a table - snippet is below.

mysql> select * from playlistfiles;
+-----------------------+--------------+-----------+
| FileName              | PlaylistName | FileIndex |
+-----------------------+--------------+-----------+
| File1                 | Image1       |         0 | 
| File1                 | Video1       |         2 | 
| File2                 | Video1       |         0 | 
| File3                 | Video1       |         1 | 
| File4                 | Image1       |         1 | 
| File4                 | Video1       |         3 | 
+-----------------------+--------------+-----------+
6 rows in set (0.00 sec)

What I need to do is to get all the FileNames and whether the file is in a playlist or not, as well as order them by FileIndex ie for the Image1 playlist, the output should be

+-----------------------+------------+-----------+
| FileName              | InPlaylist | FileIndex |
+-----------------------+------------+-----------+
| File1                 |          1 |         0 | 
| File2                 |          0 |      Null | 
| File3                 |          0 |      Null | 
| File4                 |          1 |         1 | 
+-----------------------+------------+-----------+

and Video1 would be

+-----------------------+------------+-----------+
| FileName              | InPlaylist | FileIndex |
+-----------------------+------------+-----------+
| File2                 |          1 |         0 | 
| File3                 |          1 |         1 | 
| File1                 |          1 |         2 | 
| File4                 |          1 |         3 | 
+-----------------------+------------+-----------+

In short, I need to be able to get all the unique FileNames from the table, and check if it is in a given table and if so, order it by FileIndex.

Answer 1

I would start with something like this and play from there:

select plf.fileName,
max(if(plf2.fileName = plf.fileName, 1, 0)) as inPlayList,
max(plf2.FileIndex)

from playlistfiles plf

left join playlistfiles plf2
on plf.fileName = plf2.fileName
and plf2.playListName = @playListName

group by plf.fileName