Query empty fields

FrancoisFrancois · 09-28-2025, 05:28 AM

Hello

With Calibre, we can query different fields.
I'm trying to query empty fields.
For example, I want to list all the books whose Author(s) field is empty. I can't find the correct syntax.
Can someone help me?

See you soon.

chaley · 09-28-2025, 08:21 AM

Moderator Notice
Moved from recipes to library management.

chaley · 09-28-2025, 08:24 AM

It would be "authors:false" if the authors field could ever be empty, which it can't. A book must always have an author. In English the author is set to "Unknown" if one isn't provided.

FrancoisFrancois · 10-03-2025, 02:16 AM

Hello

Thank you very much for this reply.
I tested it with false on random fields and it works. It's GREAT.

Indeed, querying empty Author fields doesn't make sense.
I should have indicated the field I wanted to query right away. It's the comment field. I tried "comment" or "comments" but it didn't work. I can't find the exact comment name to find books without comments.

Any ideas?

See you soon.

Karellen · 10-03-2025, 02:46 AM

Should be comments:false

You can find the correct names in Preferences>Look&Feel>Book Details. It will be the name in brackets.

09-28-2025, 05:28 AM	#1
FrancoisFrancois Junior Member Posts: 4 Karma: 10 Join Date: Aug 2018 Device: Calibre	Query empty fields Hello With Calibre, we can query different fields. I'm trying to query empty fields. For example, I want to list all the books whose Author(s) field is empty. I can't find the correct syntax. Can someone help me? See you soon.

10-03-2025, 02:46 AM	#5
Karellen Wizard Posts: 1,654 Karma: 9500498 Join Date: Sep 2021 Location: Australia Device: Kobo Libra 2	Should be comments:false You can find the correct names in Preferences>Look&Feel>Book Details. It will be the name in brackets. Attached Thumbnails

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
How to prevent metadata download from replacing data with empty fields?	Naed	Library Management	4	03-28-2021 03:23 AM
How can I sort a column so 'empty' fields are last?	capnm	Library Management	4	02-07-2017 12:08 AM
Download metadata - but write only empty fields?	shadowtree	Calibre	16	11-30-2013 03:06 PM
Find empty fields	ebuddelm	Library Management	2	09-22-2012 07:48 AM

09-28-2025, 08:21 AM	#2
chaley Grand Sorcerer Posts: 12,523 Karma: 8065948 Join Date: Jan 2010 Location: Notts, England Device: Kobo Libra 2	Moderator Notice Moved from recipes to library management.

09-28-2025, 08:24 AM	#3
chaley Grand Sorcerer Posts: 12,523 Karma: 8065948 Join Date: Jan 2010 Location: Notts, England Device: Kobo Libra 2	It would be "authors:false" if the authors field could ever be empty, which it can't. A book must always have an author. In English the author is set to "Unknown" if one isn't provided.

10-03-2025, 02:16 AM	#4
FrancoisFrancois Junior Member Posts: 4 Karma: 10 Join Date: Aug 2018 Device: Calibre	Hello Thank you very much for this reply. I tested it with false on random fields and it works. It's GREAT. Indeed, querying empty Author fields doesn't make sense. I should have indicated the field I wanted to query right away. It's the comment field. I tried "comment" or "comments" but it didn't work. I can't find the exact comment name to find books without comments. Any ideas? See you soon.

Advert

Advert