从具有where条件的表中查找不同数据的Linq查询
本文关键字:数据 查询 Linq 查找 where 条件 | 更新日期: 2023-09-27 18:22:10
我有一个sql语句,如下所示:
select distinct(agent_name)
from properties
where agent_name not in ('null','')
我想要C#页面中的linq查询
假设您像原始查询一样与字符串值'null'
进行比较:
List<string> agentNames = db.Properties.Where(p=>p.AgentName != "null" &&
p.AgentName != "")
.Select(p => p.AgentName)
.Distinct()
.ToList();
如果你真的在与一个空值进行比较,只需将其更改为:
List<string> agentNames = db.Properties.Where(p=>p.AgentName != null &&
p.AgentName != "")
.Select(p => p.AgentName)
.Distinct()
.ToList();
var result = context.Properties.Where(p => p.AgentName != null
&& p.AgentName != "")
.GroupBy(p => p.AgentName)
.Select(g => g.Key);
试试这样的
var result = (from dbo in database.Table
where dbo.agent_name!=null and dbo.agent_name !=''
select dbo.agent_name).Distinct();
或者如果你已经有一个列表
var result = (list.Where(a => a.agent_name!=null && a.agent_name!='').Select(
a.agent_name)).Distinct();
您可以像这样使用
var forms = db.properties.
Where(a => a.agent_name == 'null' || a.agent_name == null).
Select(x => x.agent_name).
Distinct().
ToList();
它的等价SQL语句是,它是由LINQ to SQL设计的
SELECT
[Distinct1].[agent_name] AS [agent_name]
FROM ( SELECT DISTINCT
[Extent1].[agent_name] AS [agent_name]
FROM [dbo].[properties] AS [Extent1]
WHERE [Extent1].[agent_name] = N'null' OR [Extent1].[agent_name] = N''
) AS [Distinct1]