How would I see which wordpress posts have a revision history without opening each one?

by

From the Revisions documentation page:

Revisions are stored in the posts table.

Revisions are stored as children of their associated post (the same thing we do for attachments). They are given a post_status of inherit, a post_type of revision, and a post_name of {parent ID}- revision(-#) for regular revisions and {parent ID}-autosave for autosaves.

So you should be able to search the wp_posts table for posts where the post_type is revision, and then grab the post_parent ID to find the original post.

Update

If you’re looking for an SQL query, here’s one I just tried that seemed to work:

SELECT ID, post_title
FROM wp_posts
WHERE ID IN (
    SELECT DISTINCT post_parent
    FROM wp_posts
    WHERE post_type="revision"
);

…assuming your posts table has the default name wp_posts.