public override void AppendTo(StringBuilder sb, ISqlDialect dialect)
        {
            if (!string.IsNullOrEmpty(Table))
            {
                sb.Append(Table);
            }
            else if (SubQuery != null)
            {
                sb.Append("(");
                SubQuery.AppendTo(sb);
                sb.Append(")");
            }

            if (!String.IsNullOrEmpty(Alias))
            {
                sb.Append(" AS " + Alias);
            }

            if (!string.IsNullOrEmpty(Joins))//support legacy join style
            {
                sb.Append(" ").Append(Joins);
            }
        }