diff --git a/adminer/db.inc.php b/adminer/db.inc.php
index 078904a5..60fb6dee 100644
--- a/adminer/db.inc.php
+++ b/adminer/db.inc.php
@@ -61,7 +61,7 @@ if ($adminer->homepage()) {
 				echo " <input type='submit' name='search' value='" . lang('Search') . "'>\n";
 				if ($adminer->operator_regexp !== null) {
 					echo "<p><label><input type='checkbox' name='regexp' value='1'" . (empty($_POST['regexp']) ? '' : ' checked') . '>' . lang('as a regular expression') . '</label>';
-					echo doc_link(['sql' => 'regexp.html', 'pgsql' => 'functions-matching.html#FUNCTIONS-POSIX-REGEXP']) . "</p>\n";
+					echo doc_link(['sql' => 'regexp.html', 'pgsql' => 'functions-matching.html#FUNCTIONS-POSIX-REGEXP', 'elastic' => "regexp-syntax.html"]) . "</p>\n";
 				}
 				echo "</div></fieldset>\n";
 				if ($_POST["search"] && $_POST["query"] != "") {
diff --git a/adminer/include/editing.inc.php b/adminer/include/editing.inc.php
index 611f94e7..7a4e0a32 100644
--- a/adminer/include/editing.inc.php
+++ b/adminer/include/editing.inc.php
@@ -556,27 +556,39 @@ function ini_bytes($ini) {
 	return $val;
 }
 
-/** Create link to database documentation
-* @param array $jush => $path
-* @param string HTML code
-* @return string HTML code
-*/
-function doc_link($paths, $text = "<sup>?</sup>") {
+/**
+ * Creates link to database documentation.
+ *
+ * @param array $paths $jush => $path
+ * @param string $text HTML code
+ *
+ * @return string HTML code
+ */
+function doc_link(array $paths, $text = "<sup>?</sup>") {
 	global $jush, $connection;
+
 	$server_info = $connection->server_info;
 	$version = preg_replace('~^(\d\.?\d).*~s', '\1', $server_info); // two most significant digits
-	$urls = array(
+
+	$urls = [
 		'sql' => "https://dev.mysql.com/doc/refman/$version/en/",
 		'sqlite' => "https://www.sqlite.org/",
 		'pgsql' => "https://www.postgresql.org/docs/$version/",
 		'mssql' => "https://msdn.microsoft.com/library/",
 		'oracle' => "https://www.oracle.com/pls/topic/lookup?ctx=db" . preg_replace('~^.* (\d+)\.(\d+)\.\d+\.\d+\.\d+.*~s', '\1\2', $server_info) . "&id=",
-	);
+		'elastic' => "https://www.elastic.co/guide/en/elasticsearch/reference/$version/",
+	];
+
 	if (preg_match('~MariaDB~', $server_info)) {
 		$urls['sql'] = "https://mariadb.com/kb/en/library/";
 		$paths['sql'] = (isset($paths['mariadb']) ? $paths['mariadb'] : str_replace(".html", "/", $paths['sql']));
 	}
-	return ($paths[$jush] ? "<a href='" . h($urls[$jush] . $paths[$jush]) . "'" . target_blank() . ">$text</a>" : "");
+
+	if (!isset($paths[$jush]) || !$paths[$jush] ) {
+		return "";
+	}
+
+	return "<a href='" . h($urls[$jush] . $paths[$jush]) . "'" . target_blank() . ">$text</a>";
 }
 
 /** Wrap gzencode() for usage in ob_start()