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[英]How to select records with MAX Id that group by multiple columns in LINQ to SQL
[英]SQL select multiple max rows value after group by
我有一個表,其中每個JunctionlistID重復多次。 每行中每個id前面都有一個JunctionlistID。 我想為ID最新的每個JunctionlistID選擇整行。 此表中總共有5列我希望在選擇該行時選擇所有列。
ID | MonitoringString| JunctionListId | area_id| CompanyProfileId
1 | 1006410001D0 | 267 | 910064 | 7
2 | 1206420001D0 | 268 | 910065 | 7
3 | 1306440001D0 | 267 | 910064 | 7
4 | 1506450001D0 | 268 | 910065 | 7
5 | 1606470001D0 | 267 | 910064 | 7
6 | 1806480001D0 | 268 | 910065 | 7
7 | 1006420001D0 | 267 | 910064 | 7
8 | 1006470001D0 | 268 | 910065 | 7
9 | 1006490001D0 | 267 | 910064 | 7
10 | 1006430001D0 | 268 | 910065 | 7
11 | 1006460001D0 | 285 | 910066 | 8
12 | 1006438001D0 | 268 | 910067 | 8
答案應該是
ID | MonitoringString| JunctionListId | area_id| CompanyProfileId
9 | 1006490001D0 | 267 | 910064 | 7
10 | 1006430001D0 | 268 | 910065 | 7
我嘗試查詢如下 -
Select ID,MonitoringString,JunctionListId,area_id,CompanyProfileId from tblMonitoring where CompanyProfileId=7
我需要在linq和SQL中同樣的查詢,如果有人知道請給我正確的解決方案。
謝謝
如果我理解正確的話,你只是想為每個公司和結ID中的最后記錄的基礎上, id
。 你可以使用row_number()
:
Select m.*
from (select m.*,
row_number() over (partition by CompanyProfileId, JunctionListId order by id desc) as seqnum
from tblMonitoring m
) m
where CompanyProfileId = 7 and seqnum = 1;
從MonitorsList 中選擇MAX(ID)ID,Max(MonitoringString)MonitoringString,Max(JunctionListID)JunctionListID,Max(area_id)area_id,Max(CompanyProfileId)CompanyProfileId, 其中CompanyProfileId = 7 Group by JunctionListID
https://dotnetfiddle.net/oiRkzO
using System;
using System.Data.Entity;
using System.Linq;
using System.Collections.Generic;
public class Program
{
public static void Main()
{
List<Item> items = new List<Item>()
{
new Item() { ID = 1, MonitoringString = "1006410001D0", JunctionListId = 267, area_id = 910064 , CompanyProfileId = 7},
new Item() { ID = 2, MonitoringString = "1206420001D0", JunctionListId = 268, area_id = 910065 , CompanyProfileId = 7},
new Item() { ID = 3, MonitoringString = "1306440001D0", JunctionListId = 267, area_id = 910064 , CompanyProfileId = 7},
new Item() { ID = 4, MonitoringString = "1506450001D0", JunctionListId = 268, area_id = 910065 , CompanyProfileId = 7},
new Item() { ID = 5, MonitoringString = "1606470001D0", JunctionListId = 267, area_id = 910064 , CompanyProfileId = 7},
new Item() { ID = 6, MonitoringString = "1806480001D0", JunctionListId = 268, area_id = 910065 , CompanyProfileId = 7},
new Item() { ID = 7, MonitoringString = "1006420001D0", JunctionListId = 267, area_id = 910064 , CompanyProfileId = 7},
new Item() { ID = 8, MonitoringString = "1006470001D0", JunctionListId = 268, area_id = 910065 , CompanyProfileId = 7},
new Item() { ID = 9, MonitoringString = "1006490001D0", JunctionListId = 267, area_id = 910064 , CompanyProfileId = 7},
new Item() { ID = 10, MonitoringString = "1006430001D0", JunctionListId = 268, area_id = 910065 , CompanyProfileId = 7},
new Item() { ID = 11, MonitoringString = "1006460001D0", JunctionListId = 285, area_id = 910066 , CompanyProfileId = 8},
new Item() { ID = 12, MonitoringString = "1006438001D0", JunctionListId = 268, area_id = 910067 , CompanyProfileId = 8},
};
var result = items.GroupBy(item => item.JunctionListId).Select(g => g.FirstOrDefault(gx => gx.ID == g.Max(x => x.ID))).ToList();
var resultCmp7 = items.Where(item => item.CompanyProfileId == 7).GroupBy(item => item.JunctionListId).Select(g => g.FirstOrDefault(gx => gx.ID == g.Max(x => x.ID))).ToList();
foreach (var item in result)
{
Console.WriteLine(string.Format("{0},{1},{2},{3}",item.ID, item.MonitoringString, item.JunctionListId,item.area_id, item.CompanyProfileId));
}
Console.WriteLine();
foreach (var item in resultCmp7)
{
Console.WriteLine(string.Format("{0},{1},{2},{3}",item.ID, item.MonitoringString, item.JunctionListId,item.area_id, item.CompanyProfileId));
}
Console.ReadLine();
}
class Item
{
public int ID { get; set; }
public string MonitoringString { get; set; }
public int JunctionListId { get; set; }
public int area_id { get; set; }
public int CompanyProfileId { get; set; }
}
}
試試這個,
SELECT COUNT(ID),MonitoringString,JunctionListId,are_id,CompanyProfileId FROM tblMonitoring WHERE CompanyProfileID ='7'GROUP BY CompanyProfileId;
對於linq,您可以執行以下操作。 (看起來你也想通過companyprofileid過濾)
var result = items.Where(x=>x.CompanyProfileId==7)
.GroupBy(x=>x.JunctionListId)
.Select(x=>x.ToList()
.OrderByDescending(c=>c.ID)
.ThenBy(c=>c.JunctionListId)
.First());
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