internal override void AppendTo(SqlStringBuilder builder)
        {
            builder.Append("CASE WHEN ");
            TestExpression.AppendTo(builder);
            builder.Append(" THEN ");
            TrueExpression.AppendTo(builder);

            if (FalseExpression != null)
            {
                builder.Append(" ELSE ");
                FalseExpression.AppendTo(builder);
            }
        }