/// <summary>
/// 添加分组表达式对象
/// </summary>
/// <param name="exp"></param>
/// <returns></returns>
public QueryParameter AddGroupExpr(GroupExpression exp)
{
this._groupExpressions.Add(exp);
return(this);
}
/// <summary>
/// 创建一个分组表达式对象
/// </summary>
/// <param name="expression"></param>
/// <returns></returns>
public static GroupExpression CreateInstance(string expression)
{
GroupExpression group = GroupBy(expression);
return(group);
}