MariaDBで否定先読みを実行しようと試み、失敗した際の出力ファイル。

regexp_result_bad.txt

MariaDB [(none)]> select regexp_replace('<img src="https://pandanote.info/wordpress/wp-content/uploads/2018/12/P_20181201_191300_vHDR_Auto_a-233x300.jpg" alt="" width="233" height="300" class="alignnone size-medium wp-image-3517" />','(?<!<a href=[^>]*>)(<img src=.*wp-image-(\\d+)[^>]*>)','<a href="https://pandanote.info/?attachment_id=\\2" rel="attachment wp-att-\\2">\\1</a>') as regexp_replace_result;
ERROR 1139 (42000): Got error 'lookbehind assertion is not fixed length at offset 18' from regexp