/// <summary>
        /// Конструктор
        /// </summary>
		public SQLStruct()
		{
			select = new SelectClass(this);
			from = new FromClass(this);
			where = new WhereClass(this);
			As = new AsClass(this);
			group = new GroupClass(this);
		}
        /// <summary>
        /// Конструктор
        /// </summary>
        /// <param name="baseGroup">Базовый класс группировки</param>
		public GroupClassOnce(GroupClass baseGroup)
		{
            this.baseGroup = baseGroup;
		}