--- a/mysqltuner.pl	2019-05-21 21:04:53.000000000 +0300
+++ b/mysqltuner.pl	2019-07-28 22:14:09.888967978 +0300
@@ -1739,7 +1739,7 @@
     my $PASS_COLUMN_NAME = 'password';
     if ( $myvar{'version'} =~ /5\.7|10\..*MariaDB*/ ) {
         $PASS_COLUMN_NAME =
-"IF(plugin='mysql_native_password', authentication_string, password)";
+"IF(plugin='mysql_native_password', authentication_string, 'password')";
     }
     debugprint "Password column = $PASS_COLUMN_NAME";