Dataview: Query by document property

[NineToes82]

What I’m trying to do

I’m trying to query files that possess particular properties. The properties themselves don’t need to have any specific value, or even a value at all (the property could be empty for all I care). I’m more concerned with whether or not those files have said property.

Things I have tried

I’ve been using this:

TABLE
WHERE file.frontmatter.related
SORT file.name ASC

…And it sort of works. It will report any files with the “related” property, so long as they have a value of some kind set, like this:

---
related: "[[some other file]]"
topics:
  - "[[grocery list]]"
tags:
  - organizer
  - status/ongoing
---

But it will not find files like this:

---
related: 
topics:
  - "[[grocery list]]"
tags:
  - organizer
  - status/ongoing
---

I’ve looked around and seen some suggestions for using “contains”, but again, I think that will only work when the property has a specific value. Unless there’s a way to use that to query files that contain said property?..

Aside from that, the questions I’ve come across are usually looking for a property with a particular value.

If an explanation is needed: I realize this is probably a really bad way to find the files I want - querying by a property name, instead of the property value.

I made the mistake of adding a really pointless, redundant property to my YAML header in a bunch of my files. So, instead of going through each file, one by one from the file tree, I’m trying to see if there’s a way I can just pull all the files that still have the property.

Thanks in advance.

[NineToes82]

I think I’ve got it:

TABLE 
WHERE contains(file.frontmatter, "related")
SORT file.name ASC

I used “contains” to check the file’s frontmatter property for the presence of “related”.

Don’t ask me how it works, but apparently it does.