小编use*_*290的帖子

使用linq查询数据表返回以下错误:CS0117:'DataSet1.map DataTable'不包含'AsEnumerable'的定义

Project包含System.Data.Datasetextensions的参考.

这是代码.

using System;
using System.Collections;
using System.ComponentModel;
using System.Configuration;
using System.Reflection;
using System.Data;
using System.Linq;
using System.Data.Linq;
using System.Data.Common;
using System.Data.DataSetExtensions;
using System.Linq.Expressions;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Data.SqlClient;

protected void Page_Load(object sender, EventArgs e)
    {
        var query1 = from mfg_nm in DataSet1.mapDataTable.AsEnumerable()

                     select mfg_nm;
}

运行它w/out AsEnumerable()导致

var query1 = from mfg_nm in DataSet1.mapDataTable

                     select mfg_nm;

CS1660:无法将lambda表达式转换为'string'类型,因为它不是委托类型

在此先感谢您的帮助

无法旋转雪花中的多个列。

这有效：

--DROP TABLE "PUBLIC".MONTHLY_SALES
create or replace table monthly_sales(empid int, amount int, month text)
    as select * from values
    (1, 10000, 'JAN'),
    (1, 400, 'JAN'),
    (2, 4500, 'JAN'),
    (2, 35000, 'JAN'),
    (1, 5000, 'FEB'),
    (1, 3000, 'FEB'),
    (2, 200, 'FEB'),
    (2, 90500, 'FEB'),
    (1, 6000, 'MAR'),
    (1, 5000, 'MAR'),
    (2, 2500, 'MAR'),
    (2, 9500, 'MAR'),
    (1, 8000, 'APR'),
    (1, 10000, 'APR'),
    (2, 800, 'APR'),
    (2, 4500, 'APR');
    
   
 SELECT * FROM monthly_sales
 pivot(
        sum(amount)
        for month in ('JAN', 'FEB', 'MAR', …