Fix for MySQL 5.7 password crash

MySQLTuner/TuningCalculator.cs

@@ -467,9 +467,22 @@ private void CheckStorageEngines()
         /// Display some security recommendations.
         /// </summary>
         [SuppressMessage("Microsoft.Globalization", "CA1303:Do not pass literals as localized parameters", Justification = "This only supports english")]
+        [SuppressMessage("Microsoft.Security", "CA2100:Review SQL queries for security vulnerabilities", Justification = "The value in the query is generated by the program")]
         private void SecurityRecommendations()
         {
-            string sql = "SELECT CONCAT(user, '@', host) AS `username` FROM mysql.user WHERE password = '' OR password IS NULL ORDER BY `username`";
+        	// Get the name of the password column
+        	string passwordColumnName;
+        	if (this.Server.Version.Major > 5 || (this.Server.Version.Major == 5 && this.Server.Version.Minor >= 7))
+        	{
+        		passwordColumnName = "authentication_string";
+        	}
+        	else
+        	{
+        		passwordColumnName = "password";
+        	}
+
+        	// Find any users with no passwords
+            string sql = "SELECT CONCAT(user, '@', host) AS `username` FROM mysql.user WHERE " + passwordColumnName + " = '' OR " + passwordColumnName + " IS NULL ORDER BY `username`";
             using (MySqlCommand command = new MySqlCommand(sql, this.Server.Connection))
             {
                 using (MySqlDataReader reader = command.ExecuteReader())