使用实体框架查找SQL表中的所有重复记录 [英] Find all duplicate records in SQL table with Entity Framework
问题描述
我有这个表:
商店
ID名称地址城市
------------------------ -----------------
1 name1地址1 city1
2名称2 adress2 city2
3名称2
4名称2 city2
5名称3
6名称4 adress4 city4
7名称4 adress4 city4
,我的datagrid必须包含:
2名称2 adress2 city2
3名称2
4名称2 city2
6名称4 adress4 city4
7名称4 adress4 city4
但是我不知道如何创建这个查询
如果你使用Entity Framework我假设你使用LINQ作为在这种情况下,请尝试以下方式:
var duplicateates = Shop.GroupBy(i => i.Name)
.Where(x => x.Count()> 1)
.Select(val => val.Key);
foreach(重复的var项目)
{
//进程
}
在一个简单的示例中,输出将如下所示:
//编辑:
通过多个列可以使用以下语法:
var query =(from sh in Shop
group sh by new { sh.Name,sh.Address,sh.City} into grp
select new
{
name = grp.Key.Name,
address = grp.Key.Address,
city = grp.Key.City
})ToList()
.GroupBy(q => q.name)
.Where(q => q.Count )> 1)
.Dump();
这将导致以下内容:
// EDIT2 :
有时我是边界愚蠢的。
遵循KISS原则:
var query = Shop.GroupBy(s => s.Name)。 Where(s => s.Count()> 1).Dump();
I want to create a datagrid which contains all the records with then same name.
I have this table:
Shop
ID name adress city
-----------------------------------------
1 name1 adress 1 city1
2 name 2 adress2 city2
3 name 2
4 name 2 city2
5 name 3
6 name 4 adress4 city4
7 name 4 adress4 city4
and my datagrid must contain:
2 name 2 adress2 city2
3 name 2
4 name 2 city2
6 name 4 adress4 city4
7 name 4 adress4 city4
but I have no idea how to create this query
If you use Entity Framework I assume you use LINQ as well.
In which case, try it this way:
var duplicates = Shop.GroupBy(i => i.Name)
.Where(x => x.Count() > 1)
.Select(val => val.Key);
foreach(var item in duplicates)
{
//process
}
In a simple example the output would look like this:
//EDIT:
if you want to group by multiple columns you can use this syntax:
var query = (from sh in Shop
group sh by new {sh.Name, sh.Address, sh.City} into grp
select new
{
name = grp.Key.Name,
address = grp.Key.Address,
city = grp.Key.City
}).ToList()
.GroupBy(q => q.name)
.Where (q => q.Count() >1)
.Dump();
This will result in the following:
//EDIT2: sometimes I am borderline stupid. Following the KISS-principle:
var query = Shop.GroupBy (s => s.Name).Where (s => s.Count () > 1).Dump();
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