What does this error mean?

I found this in my debug.log

[06-Mar-2016 06:36:32 UTC] WordPress database error Unknown column 'wp_posts.post_type' in 'where clause' for query SELECT SQL_CALC_FOUND_ROWS wp2_posts.ID FROM wp2_posts INNER JOIN wp2_postmeta ON (wp2_posts.ID = wp2_postmeta.post_id) WHERE 1=1 AND (((wp2_posts.post_title LIKE '%12231%') OR (post_excerpt LIKE '%12231%') OR (wp2_posts.post_content LIKE '%12231%'))) AND (wp2_posts.post_password = '') AND wp2_posts.post_type = 'product' AND (wp2_posts.post_status = 'publish') AND ( (wp2_postmeta.meta_key = '_visibility' AND CAST(wp2_postmeta.meta_value AS CHAR) IN ('visible','search')) ) AND wp_posts.post_type NOT IN ('page') GROUP BY wp2_posts.ID ORDER BY wp2_posts.menu_order ASC, wp2_posts.post_title ASC LIMIT 0, 12 made by require('wp-blog-header.php'), wp, WP->main, WP->query_posts, WP_Query->query, WP_Query->get_posts