VB.NET中按日期分类汇总问题
各位大哥,我是初学者
我在VB.NET中做了一个按日期查询汇总,但是总是提法我的查询日期字段不在ＧＲＯＵＰ　ＢＹ　中，但是如果把它加进去那就没有汇总啊，请问怎么样才能解决啊，对了，还有一个问题，我的日期是直接输入到文本框中的，有什么方法可以直接选择进去，谢谢了，在线等
cmd.CommandText += "where purchaser like '% " + purchaser + "% ' and material_specification like '% " + specification + "% ' "
cmd.CommandText += " and material_name like '% " + name + "% ' "
cmd.CommandText += " and kind like '% " + kind + "% ' "
cmd.CommandText += " and in_time between ' " + begint + " ' "
cmd.CommandText += " and ' " + endt + " ' group by material_name,material_specification,purchaser,kind ,in_time order by purchaser,material_name,material_specification "
cmd.Connection = conn

如果不加ＩＮ＿ＴＩＭＥ就报错

[解决办法]
1. in_time> = ' " + begint + " ' " and in_time <= ' " + endt + " '
2. 用DataTimePicker