如何首先在EF 4.1代码中使用复杂的SQL查询

Question

We have just started using EF 4.1 code first. I have a sql query something like this:

SELECT * FROM TableA  
WHERE DATEDIFF(DAY,GETDATE(), TableA.ExpirationDate == x days)

I don't know how to use sql query with EF 4.1 code first set of functions. One function like this:

IQueryable<TEntity> GetQuery<TEntity>() where TEntity : class 

Does anybody has an idea?

Answer 1

Something like this is close to your query:

var things = context.TableAEntities
    .Where(e => EntityFunctions.DiffDays(DateTime.Now, e.ExpirationDate) == x)
    .ToList();

It translates to:

SELECT 
[Extent1].[Id] AS [Id], 
//... more columns
[Extent1].[ExpirationDate] AS [ExpirationDate]
FROM [dbo].[TableA] AS [Extent1]
WHERE (DATEDIFF (day, SysDateTime(), [Extent1].[ExpirationDate])) = @p__linq__0

SysDateTime() (in SQL Server) is the same as GETDATE() , it just has a higher precision.

Answer 2

Try

context.Database.SqlQuery<EntityA>("SELECT * FROM TableA
WHERE DATEDIFF(DAY,GETDATE(), TableA.ExpirationDate == x days");