如何在实体框架中使用 <> 表达式

Question

We need to convert following query to Entity framework syntax based query but not fond any alternative for '<>' condition:

Query:

        select (FirstName+' '+LastName) AS Name ,WorksNumber from [TSHumanResource] 
    join [TSUserProfile] on [TSUserProfile].[TSPersonID] = [TSHumanResource].[TSPersonID] 
    join [TSPerson] on [TSPerson].[TSPersonID] = [TSHumanResource].[TSPersonID] 
    where [TSUserProfile].[TSUserStatusID] = 1 
and [EmployeeReference] <> ' ' and [MMSUserID] is not null order by [WorksNumber] asc

Here's what I was tring:

        (from HR in oDB.TSHumanResources
         join UP in oDB.TSUserProfiles on HR.TSPersonID equals UP.TSPersonID
         join P in oDB.TSPersons on HR.TSPersonID equals P.TSPersonID
         where UP.TSUserStatusID == 1 && HR.EmployeeReference <>
         select new
         {
             ID = e.TSPersonID ,
             ID = e.TID,
         }).Take(10);

Answer 1

The SQL Server operator <> means not equal . In c#, the not equal operator is written like this: != .

You have another problem in your linq query - you are currently doing an inner join instead of a left join .

A left join in LINQ is a bit cumbersome comparing to a left join in SQL - it has to go through a group join first. Your query should look more like this:

from hr in TSHumanResource
join up in TSUserProfile on hr.TSPersonID equals up.TSPersonID into upgroup
from upg in upgroup.DefaultIfEmpty()
join p in TSPerson on upg.TSPersonID equals p.TSPersonID into pgroup
from puphr in pgroup.DefaultIfEmpty()
where up.TSUserStatusID = 1 
&& HR.EmployeeReference != " " // Assuming you want it different than a single space
// Other conditions here - I don't know where MMSUserID belongs to
order by hr.WorksNumber // just guessing here - I don't know if it's from hr