Access 表和查询 数据表视图的合计行计算可使用的聚合函数
0 = Sum (合计）
1 = Average (平均值）
2 = Count (计数）
3 = Maximum (最大值)
4 = Minimum (最小值)
5 = Standard Deviation (标准偏差)
6 = Variance (方差)
特别注意 : 可选的聚合函数取决于你选择的列的数据类型（字段类型）;
AutoNumber = None / Count
Text = None / Count
Date = None / Average / Count / Maximum / Minimum
Number = None / Sum / Average / Count / Maximum / Minimum / Standard Deviation / Variance
Currency = None / Sum / Average / Count / Maximum / Minimum / Standard Deviation / Variance
Yes/No = None / Count
OLEObject = None / Count
Hyperlink = None / Count
Attachment = None / Count
Memo = None / Count
