Error log and SQL inject attempts

Not long after I delete my error log, new ones appear with messages of what I think is failed attempts of SQL inject (not sure). I suspect that it’s bots crawling sites looking for weaknesses. Is there any clever way to prevent this and keep a clean error log? I want to avoid installing plugins like Wordfence because I try to keep plugins at a minimum, especially heavier ones.

Not sure what they even do for the error message to appear? Add the SQL command in the login field? Search box?

The error looks like this…

[08-Mar-2024 03:44:07 UTC] WordPress database error Regex error 'quantifier does not follow a repeatable item at offset 2' for query
SELECT SQL_CALC_FOUND_ROWS DISTINCT wp_posts.ID
FROM wp_posts LEFT JOIN wp_term_relationships AS tr ON (wp_posts.ID = tr.object_id)
WHERE 1=1 AND (
wp_posts.ID NOT IN (
SELECT object_id
FROM wp_term_relationships
WHERE term_taxonomy_id IN (792)
)
AND
wp_posts.ID NOT IN (
SELECT object_id
FROM wp_term_relationships
WHERE term_taxonomy_id IN (792)
)
) AND ( ((wp_posts.post_title REGEXP '\b試験の準備方法-実用的なMB-220|試験の準備方法-実用的なMB-220\b')) AND ((wp_posts.post_title REGEXP '\b資格模擬試験-真実的なMB-220|資格模擬試験-真実的なMB-220\b')) AND ((wp_posts.post_title REGEXP '\b認定テキスト|認定テキスト\b')) AND ((wp_posts.post_title REGEXP '\b?|?\b')) AND ((wp_posts.post_title REGEXP '\b➽|➽\b')) AND ((wp_posts.post_title REGEXP '\bwww.spamURL.com|www.goshiken.com\b')) AND ((wp_posts.post_title REGEXP '\b?で《|?で《\b')) AND ((wp_posts.post_title REGEXP '\bMB-220|MB-220\b')) AND ((wp_posts.post_title REGEXP '\b》を検索し、無料でダウンロードしてくださいMB-220受験対策|》を検索し、無料でダウンロードしてくださいMB-220受験対策\b'))) AND ( ( wp_posts.ID NOT IN ( SELECT wp_term_relationships.object_id FROM wp_term_relationships WHERE wp_term_relationships.term_taxonomy_id IN ( 792) ) )) AND wp_posts.post_type="post" AND ((wp_posts.post_status="publish" OR wp_posts.post_status="inherit"))
GROUP BY wp_posts.ID
ORDER BY (CASE WHEN wp_posts.post_title LIKE '%試験の準備方法-実用的なMB-220 資格模擬試験-真実的なMB-220 認定テキスト ? ➽ www.goshiken.com ?で《 MB-220 》を検索し、無料でダウンロードしてくださいMB-220受験対策%' THEN 1 WHEN wp_posts.post_excerpt LIKE '%試験の準備方法-実用的なMB-220 資格模擬試験-真実的なMB-220 認定テキスト ? ➽ www.spamURL.com ?で《 MB-220 》を検索し、無料でダウンロードしてくださいMB-220受験対策%' THEN 4 WHEN wp_posts.post_content LIKE '%試験の準備方法-実用的なMB-220 資格模擬試験-真実的なMB-220 認定テキスト ? ➽ www.spamURL.com ?で《 MB-220 》を検索し、無料でダウンロードしてくださいMB-220受験対策%' THEN 5 ELSE 6 END), wp_posts.post_date DESC
LIMIT 0, 8
made by require('wp-blog-header.php'), wp, WP->main, WP->query_posts, WP_Query->query, WP_Query->get_posts