replace blank/empty/nNULL titles with the_excerpt()

Im looking for a plugin or even a sql query(since its like a one time thing) that will parse all post titles, and if it is “empty/blank/null” it will replace it with the_excerpt(like 5 words deep) permenantly in the database, not a clientside replace?

A plugin would be nice so that it could always be looking so when you post with no title it would automatically add the_excerpt(with a setting for #chars).

I am trying to get 20 years of posts that were made before using titles for each.