Obsidian works with what is called a vault, i.e. a project folder. You can then search for text across all the notes in a vault. No need to remember the date.
In addition to that, you can work with hash tags inside the notes and then filter files based on tags, e.g. #sql-query or so.
In addition to that, you can work with hash tags inside the notes and then filter files based on tags, e.g. #sql-query or so.