When the tag retrieval was done effectively and retrieved, the following were output to the error log of Apache.
WordPress \xe3\x83\x87\xe3\x83\xbc\xe3\x82\xbf\xe3\x83\x99\xe3\x83\xbc\xe3\x82\xb9\xe3\x82\xa8\xe3\x83\xa9\xe3\x83\xbc: Not unique table/alias: 'trel' for query 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 = 'category' OR 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_term_relationships AS trel ON (wp_posts.ID = trel.object_id) LEFT JOIN wp_term_taxonomy AS ttax ON ( ( ttax.taxonomy = 'category' OR 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_postmeta AS m ON (wp_posts.ID = m.post_id) LEFT JOIN wp_users AS u ON (wp_posts.post_author = u.ID) WHERE 1=1 AND ( ((((wp_posts.post_title LIKE '%words%') OR (u.user_nicename LIKE '%words%') OR (wp_posts.post_content LIKE '%words%'))) OR (((tter.name LIKE '%words%') OR (tter.slug LIKE '%25words%25'))) OR ((tter.slug LIKE '%words%')) OR ((ttax.description LIKE '%words%')) OR ((m.meta_value LIKE '%words%')) OR ((wp_posts.post_excerpt LIKE '%words%')) ) AND wp_posts.post_type != 'revision' AND (wp_posts.post_status = 'publish' OR wp_posts.post_author = 2 AND wp_posts.post_status = 'private')) AND post_type != 'revision' ORDER BY wp_posts.post_date DESC LIMIT 0, 7 made by require, wp, WP->main, WP->query_posts, WP_Query->query, WP_Query->get_posts, referer: https://exsample.com