主题：SQLGroupTableBuilder统计问题,请教老师

Dim bd1 As New SQLGroupTableBuilder("统计表1","明细")
Dim dt1 As fxDataSource
bd1.C
bd1.Groups.AddDef("日期",DateGroupEnum.Year,"日期_年")

bd1.Groups.AddDef("日期","日期_月")

根据以上代码,学生想让"日期_年"列中不生成数据,但列保留该怎么调整