Just a minor point of clarification, as it may catch you out in the future.
The [Playlists] field is a bit of a special case. It doesn't actually exist in the Main MC database. You can easily check that by going to "Options > Library & Folders > Manage Library Fields" then try to find it. You won't, even with "Show all fields (including hidden fields)" selected in the drop-down list.
My understanding is that there is a separate table/database for Playlists, and in that is a list of Playlists names, against which the "File Key"
1 for each file on the Playlist is listed.
So basically, MC doesn't look up the File first as it normally does, and then list all Playlists associated with it, but looks up a Playlist and then lists all Files associated with that Playlist. So it is sort of a reverse lookup, though obviously when using the basic [Playlists] column header in a View/Playlist/Smartlist, MC is looking up that table for any instances of the File Key, and then listing which Playlists it is associated with.
Anyway, that is my understanding, and no-one has corrected me on that yet!
Most of the time the above won't affect your use of the [Playlists] field, but sometimes it won't be available to you. I had an example a while back trying to help build a Playlist of files that aren't on a list of existing Playlists. This one:
https://yabb.jriver.com/interact/index.php/topic,124411.0.htmlNote 1:
The "File Key" is a unique number assigned to every record in the Library. You can see it by adding an Expression column to a View/Playlist/Smartlist with the expression "FileKey()".