query result what should i use Count() or Any()

I am checking开发者_开发知识库 login of a user by this repository method,

  public bool getLoginStatus(string emailId, string password)
    {
        var query = from r in taxidb.Registrations
                    where (r.EmailId == emailId && r.Password==password)
                    select r;
        if (query.Count() != 0)
        {
            return true;
        }
        return false;
    }

I saw in one of the previous questions !query.Any() would be faster... Which should i use? Any suggestion....

The sql generated will be different between the two calls. You can check by setting your context.Log property to Console.Out or something.

Here's what it will be:

SELECT COUNT(*) AS [value]
FROM [dbo].[Registrations] AS [t0]
WHERE [t0].[EmailId] = @p0 and [t0].Password = @p1

SELECT 
    (CASE 
        WHEN EXISTS(
            SELECT NULL AS [EMPTY]
            FROM [dbo].[Registrations] AS [t0]
            WHERE [t0].[EmailId] = @p0 and [t0].Password = @p1
            ) THEN 1
        ELSE 0
     END) AS [value]

In this case, I doubt it will make any difference because EmailID is probably a unique index so there can only be 1 result. In another case where count can be > 1, Any would be preferable because the second query allows sql server to short circuit the search since it only needs to find one to prove that any exist.

You could express it quite a bit shorter like this:

return taxidb.Registrations.Any(r => r.EmailId == emailId && r.Password==password);