从asp.net中的数据表中选择

问题描述

好的..还有一个问题是，



我有onedatatable列是ruleid，descp



和在seconddatatable，我有列hotelid，ruleid



现在我想检查



如果secondtable.contains hotelid，选择ruleid，如果（onedatatable.contains ruleid from seconddatatable，选择descp in onedatatable）



i希望你明白..

ok..one other question is ,

I have onedatatable where column is ruleid,descp

and in seconddatatable, i have column hotelid,ruleid

now i want to check

if secondtable.contains hotelid,select ruleid and,if(onedatatable.contains ruleid from seconddatatable,select descp in onedatatable)

i hope u understood..

推荐答案

DataTable dtOne = new DataTable();
dtOne.Columns.Add("ruleid", typeof(int));
dtOne.Columns.Add("descp", typeof(string));
dtOne.Rows.Add(1, "hello");
dtOne.Rows.Add(2, "there");
dtOne.Rows.Add(3, "world");

DataTable dtTwo = new DataTable();
dtTwo.Columns.Add("hotelid", typeof(int));
dtTwo.Columns.Add("ruleid", typeof(int));
dtTwo.Rows.Add(1, 1);
dtTwo.Rows.Add(2, 1);
dtTwo.Rows.Add(3, 2);
dtTwo.Rows.Add(4, 3);
dtTwo.Rows.Add(5, 4);

var results = from rowOne in dtOne.AsEnumerable()
              join rowTwo in dtTwo.AsEnumerable() on rowOne.Field<int>("ruleId") equals rowTwo.Field<int>("ruleid")
              where rowTwo.Field<int>("hotelid") == 3
              select new { hotelid = rowTwo["hotelid"], descp = rowOne["descp"] };

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