How can I search for notes using the built-in search plugin, which supports regex, to search for notes that have no entry in specific keys within the frontmatter?
I am using templater and thus am using my frontmatter looks like this:
---
aliases:
publish: false
tag:
---
%%
date:: [[2023-07-11 Tue]]
parent:: [[XYZ]]
%%
Searching for "parent:: " works fine, but I want to find notes that do not have a parent note yet. For this I tried parent:: /$ as indicated here and here, but this and other variations like parent:: /\$/ do not yield any results.