Phân tách các từ ra để tìm kiếm giống với tìm kiếm post_title, post_excerpt, post_content phần 1(ok)

C:\xampp\htdocs\wordpress1\wp-content\themes\twentytwentyone\functions.php

// === Phân tách các từ ra để tìm kiếm ===
if(!class_exists('parse_search_custom')) {
	class parse_search_custom {
		function parse_search($s) {
			$q = array();
			$q['s'] = $s;
		  global $wpdb;
		  $search = '';
		  // Added slashes screw with quote grouping when done early, so done later.
		  $q['s'] = stripslashes($q['s']);
		  if (empty($_GET['s']) && is_main_query()) {
		    $q['s'] = urldecode($q['s']);
		  }
		  // There are no line breaks in <input /> fields.
		  $q['s']                  = str_replace(array("\r", "\n"), '', $q['s']);
		  $q['search_terms_count'] = 1;
		  if (!empty($q['sentence'])) {
		    $q['search_terms'] = array($q['s']);
		  } else {
		    if (preg_match_all('/".*?("|$)|((?<=[\t ",+])|^)[^\t ",+]+/', $q['s'], $matches)) {
		      $q['search_terms_count'] = count($matches[0]);
		      $q['search_terms']       = $this->parse_search_terms($matches[0]);
		      // If the search string has only short terms or stopwords, or is 10+ terms long, match it as sentence.
		      if (empty($q['search_terms']) || count($q['search_terms']) > 9) {
		        $q['search_terms'] = array($q['s']);
		      }
		    } else {
		      $q['search_terms'] = array($q['s']);
		    }
		  }
		  $n                         = !empty($q['exact']) ? '' : '%';
		  $searchand                 = '';
		  $q['search_orderby_title'] = array();
		  /**
		   * Filters the prefix that indicates that a search term should be excluded from results.
		   *
		   * @since 4.7.0
		   *
		   * @param string $exclusion_prefix The prefix. Default '-'. Returning
		   *                                 an empty value disables exclusions.
		   */
		  $exclusion_prefix = apply_filters('wp_query_search_exclusion_prefix', '-');
		  foreach ($q['search_terms'] as $term) {
		    // If there is an $exclusion_prefix, terms prefixed with it should be excluded.
		    $exclude = $exclusion_prefix && (substr($term, 0, 1) === $exclusion_prefix);
		    if ($exclude) {
		      $like_op  = 'NOT LIKE';
		      $andor_op = 'AND';
		      $term     = substr($term, 1);
		    } else {
		      $like_op  = 'LIKE';
		      $andor_op = 'OR';
		    }
		    if ($n && !$exclude) {
		      $like                        = '%' . $wpdb->esc_like($term) . '%';
		      $q['search_orderby_title'][] = $wpdb->prepare("{$wpdb->posts}.post_title LIKE %s", $like);
		    }
		    $like = $n . $wpdb->esc_like($term) . $n;
		    $search .= $wpdb->prepare("{$searchand}(({$wpdb->posts}.post_title $like_op %s) $andor_op ({$wpdb->posts}.post_excerpt $like_op %s) $andor_op ({$wpdb->posts}.post_content $like_op %s))", $like, $like, $like);
		    $searchand = ' AND ';
		  }
		  return $search;
		}
		function parse_search_terms($terms) {
		  $strtolower = function_exists('mb_strtolower') ? 'mb_strtolower' : 'strtolower';
		  $checked    = array();
		  $stopwords = $this->get_search_stopwords();
		  foreach ($terms as $term) {
		    // Keep before/after spaces when term is for exact match.
		    if (preg_match('/^".+"$/', $term)) {
		      $term = trim($term, "\"'");
		    } else {
		      $term = trim($term, "\"' ");
		    }
		    // Avoid single A-Z and single dashes.
		    if (!$term || (1 === strlen($term) && preg_match('/^[a-z\-]$/i', $term))) {
		      continue;
		    }
		    if (in_array(call_user_func($strtolower, $term), $stopwords, true)) {
		      continue;
		    }
		    $checked[] = $term;
		  }
		  return $checked;
		}
		function get_search_stopwords() {
		  /*
		   * translators: This is a comma-separated list of very common words that should be excluded from a search,
		   * like a, an, and the. These are usually called "stopwords". You should not simply translate these individual
		   * words into your language. Instead, look for and provide commonly accepted stopwords in your language.
		   */
		  $words = explode(
		    ',',_x('about,an,are,as,at,be,by,com,for,from,how,in,is,it,of,on,or,that,the,this,to,was,what,when,where,who,will,with,www','Comma-separated list of search stopwords in your language')
		  );
		  $stopwords = array();
		  foreach ($words as $word) {
		    $word = trim($word, "\r\n\t ");
		    if ($word) {
		      $stopwords[] = $word;
		    }
		  }
		  /**
		   * Filters stopwords used when parsing search terms.
		   *
		   * @since 3.7.0
		   *
		   * @param string[] $stopwords Array of stopwords.
		   */
		  $stopwords = apply_filters('wp_search_stopwords_ct', $stopwords);
		  return $stopwords;
		}
	}
}

C:\xampp\htdocs\wordpress1\wp-content\themes\twentytwentyone\header.php

<?php  
  if(class_exists('parse_search_custom')) {
    echo '<pre>';
      $test = new parse_search_custom();
      var_export($test->parse_search("Lorem ipsum dolor."));
    echo '</pre>';
  }else{
    echo "Không";
  };
?>

Kết quả:

AND (
  (
    (wp_posts.post_title LIKE "Lorem") 
    OR (wp_posts.post_excerpt LIKE "Lorem") 
    OR (wp_posts.post_content LIKE "Lorem")
  ) 
AND (
    (wp_posts.post_title LIKE "ipsum") 
    OR 
    (wp_posts.post_excerpt LIKE "ipsum") 
    OR (wp_posts.post_content LIKE "ipsum")
  ) 
AND (
    (wp_posts.post_title LIKE "dolor.") 
    OR (wp_posts.post_excerpt LIKE "dolor.") 
    OR (wp_posts.post_content LIKE "dolor.")
  )
)  
AND (wp_posts.post_password = "")