Unknown and Unexplained parse error

I came to check on my site today, and within the last 24 hours something has happened to WordPress to make it display this error.

Database error: [Got error 28 from table handler]
SELECT DISTINCT * FROM wp_posts WHERE 1=1 AND post_date_gmt <= '2005-06-27 22:34:59' AND (post_status = "publish") GROUP BY wp_posts.ID ORDER BY post_date DESC LIMIT 3

I don’t know much about PHP and MySQL and don’t understand what this error is saying, or why it’s there in the first place. I haven’t touched any of the code or the SQL databases, so I have no idea why this would be here. No additional posts or comments have been made; this just suddenly appeared, and I have no idea how to fix it.