I reported this for version 2.4 and 2.5, but there was no followup and it's still an issue.
On WordPress 2.5.1, if you have your WP Recent Posts widget (stock) activated on your WP Sidebar and you search, all of the results pages return the following code:
[blockquote]WordPress database error: [You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '(wp_posts.post_status = 'publish') OR ( tter.name LIKE '%search-everything%') O' at line 1]
SELECT DISTINCT SQL_CALC_FOUND_ROWS wp_posts.* FROM wp_posts LEFT JOIN wp_term_relationships AS trel ON (wp_posts.ID = trel.object_id) LEFT JOIN wp_term_taxonomy AS ttax ON ( ( ttax.taxonomy = 'post_tag' ) AND trel.term_taxonomy_id = ttax.term_taxonomy_id) LEFT JOIN wp_terms AS tter ON (ttax.term_id = tter.term_id) LEFT JOIN wp_comments AS c ON ( comment_post_ID = ID ) WHERE 1=1 AND wp_posts.(wp_posts.post_status = 'publish') OR ( tter.name LIKE '%search-everything%') OR ( c.comment_post_ID = wp_posts.ID AND c.comment_approved = '1' AND c.comment_content LIKE '%search everything%') ORDER BY wp_posts.post_date DESC LIMIT 0, 5[/blockquote]