[英]Using LINQ get the differences between two tables
我有一个现有表和一个新表。 这些表至少包含两个需要检查的项目。 我需要做以下几件事
1)获取不在新表中但在现有表中的项目列表。 -因此可以将其删除2)获取新表中但现有表中没有的项目列表-这样就可以添加它们
3)获取两个表中的项目列表,但现有表需要更新
这是数据
var existingItems = new[]
{
new RetryItem { CellId = 1, Content = "Bob" },
new RetryItem { CellId = 2, Content = "Bill" },
new RetryItem { CellId = 3, Content = "Frank" },
new RetryItem { CellId = 4, Content = "Tom" },
new RetryItem { CellId = 5, Content = "Dick" },
new RetryItem { CellId = 6, Content = "Harry" },
};
var newItemsLarger = new[]
{
new RetryItem { CellId = 1, Content = "Bob" },
new RetryItem { CellId = 2, Content = "Bill" },
new RetryItem { CellId = 3, Content = "Frank" },
new RetryItem { CellId = 4, Content = "Tom now Thoams" },
new RetryItem { CellId = 5, Content = "Dick now Dicky" },
new RetryItem { CellId = 6, Content = "Harry Now Harriet" },
new RetryItem { CellId = 7, Content = "Mary" },
new RetryItem { CellId = 8, Content = "Mungo" },
new RetryItem { CellId = 9, Content = "Midge" },
};
我认为这些可能会满足您的需求:
1)
var q1 = from c1 in existingItems
join c2 in newItemsLarger
on new { c1.CellId, c1.Content } equals new {c2.CellId, c2.Content }
select c1;
2)
var q2 = from c1 in newItemsLarger
where !existingItems.Select(x => x.CellId).Contains(c1.CellId)
select c1;
3)
var q3 = from c1 in existingItems
join c2 in newItemsLarger on c1.CellId equals c2.CellId
where c1.Content != c2.Content
select c2;
您可以在控制台应用程序中使用以下示例程序:
using System.Linq;
namespace ExperimentConsoleApp
{
class Program
{
static void Main()
{
// Check if the item is in existingItems but not in newItems
var itemsToBeRemoved = (from e in existingItems
where !newItemsLarger.Any(n => n.CellId == e.CellId)
select e).ToList();
// Check if the item is in newItems but not in existingItems
var itemsToBeAdded = (from n in newItemsLarger
where !existingItems.Any(e => n.CellId == e.CellId)
select n).ToList();
// Match the items on Id and check if their contents equals
var itemsToBeUpdated = (from e in existingItems
from n in newItemsLarger
where e.CellId == n.CellId && e.Content != n.Content
select n).ToList();
}
static RetryItem[] existingItems = new[]
{
new RetryItem { CellId = 1, Content = "Bob" },
new RetryItem { CellId = 2, Content = "Bill" },
new RetryItem { CellId = 3, Content = "Frank" },
new RetryItem { CellId = 4, Content = "Tom" },
new RetryItem { CellId = 5, Content = "Dick" },
new RetryItem { CellId = 6, Content = "Harry" },
};
static RetryItem[] newItemsLarger = new[]
{
new RetryItem { CellId = 1, Content = "Bob" },
new RetryItem { CellId = 3, Content = "Frank" },
new RetryItem { CellId = 4, Content = "Tom now Thoams" },
new RetryItem { CellId = 5, Content = "Dick now Dicky" },
new RetryItem { CellId = 6, Content = "Harry Now Harriet" },
new RetryItem { CellId = 7, Content = "Mary" },
new RetryItem { CellId = 8, Content = "Mungo" },
new RetryItem { CellId = 9, Content = "Midge" },
};
}
public class RetryItem
{
public int CellId { get; set; }
public string Content { get; set; }
}
}
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.