Fix: time based sorting

org-roam-ql.el

@@ -519,6 +519,13 @@ DOCSTRING is the documentation string to use for the function."
  `(lambda (node1 node2)
  (,comparison-function-name (,getter node1) (,getter node2))))))
 
+(defun org-roam-ql--sort-time-less (val1 val2)
+ "Sort based on time-less-p."
+ (if (or (null val1) (null val2))
+ nil
+ (time-less-p (org-roam-ql--time-convert-to-ts val1)
+ (org-roam-ql--time-convert-to-ts val2))))
+
 ;; *****************************************************************************
 ;; org-roam-ql mode and functions to build them and operate on them
 ;; *****************************************************************************
@@ -1087,10 +1094,10 @@ Can be used in the minibuffer or when writting querries."
  ("file-title" . string<)
  ("level" . <)
  ("point" . <)
- ("scheduled" . time-less-p)
- ("deadline" . time-less-p)
- ("file-atime" . time-less-p)
- ("file-mtime" . time-less-p)))
+ ("scheduled" . org-roam-ql--sort-time-less)
+ ("deadline" . org-roam-ql--sort-time-less)
+ ("file-atime" . org-roam-ql--sort-time-less)
+ ("file-mtime" . org-roam-ql--sort-time-less)))
  (org-roam-ql--sort-function-for-slot (car sort-function) (cdr sort-function)))
 
 (provide 'org-roam-ql)