Question

如何在 Linq 中编写此查询？

SELECT e.STARTDATE,
       e.REASON,
       s.DESCRIPTION  
  FROM E_JOURNAL j inner join 
       E_ABSENCE e on j.JOURNALID = e.JOURNALID AND 
               e.ABSENCEHISTORYID = (SELECT MAX(ABSENCEHISTORYID) 
                                       FROM E_ABSENCE 
                                      WHERE JOURNALID = j.JOURNALID) INNER JOIN 
       E_STATUS s on j.CURRENTITEMSTATUSID = s.ITEMSTATUSID INNER JOIN 
       E_NATURE n on j.ITEMNATUREID = n.ITEMNATUREID 
 WHERE j.EMPLOYEEID = 113

Answer 1

尝试这样的代码

using System.Collections.ObjectModel;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;

namespace ConsoleApplication57
{
    class Program
    {
        static void Main(string[] args)
        {
            int employeeId = 113;

            List<E_JOURNAL> employee = E_JOURNAL.journals.Where(x => x.JOURNALID == employeeId).ToList();

            var results = (from j in employee
                           join s in E_ABSENCE.absenses on j.JOURNALID equals s.JOURNALID
                           orderby s.ABSENCEHISTORYID descending
                           select new {
                               startDate = s.STARTDATE,
                               reason = s.REASON,
                                description = E_STATUS.statuses.Where(x => x.CURRENTITEMSTATUSID == j.CURRENTITEMSTATUSID).Select(x => x.DESCRIPTION).FirstOrDefault()
                           }).FirstOrDefault();
        }

    }
    public class E_JOURNAL
    {
        public static List<E_JOURNAL> journals = new List<E_JOURNAL>();

        public int JOURNALID { get; set; }
        public int ITEMNATUREID { get; set; }
        public int EMPLOYEEID { get; set; }
        public int CURRENTITEMSTATUSID { get; set; }

    }
    public class E_STATUS
    {
        public static List<E_STATUS > statuses = new List<E_STATUS>();

        public string DESCRIPTION { get; set; }
        public int CURRENTITEMSTATUSID { get; set; }

    }
    public class E_ABSENCE
    {
        public static List<E_ABSENCE> absenses = new List<E_ABSENCE>();

        public int JOURNALID { get; set; }
        public DateTime STARTDATE { get; set; }
        public string REASON { get; set; }
        public int ABSENCEHISTORYID { get; set; }
    }
    public class E_NATURE
    {
        public static List<E_NATURE> natures = new List<E_NATURE>();

        public int ITEMNATUREID { get; set; }
    }

}

加入linq中的多个键

1 个答案: