Converting SQL to LINQ with Min and Max functions

Question

I have the following SQL snippet that I am trying to convert to a LINQ query as part of a more complex query but I cannot see how to get started:

SELECT
    AT.PrimaryIDChanged AS PID,
    MAX(AT.ProcessID) AS EventTypeID,
    MIN(AT.AuditDateTime) AS EventDate
FROM
    dbo.AuditTrail AS AT    
WHERE
    AT.AuditTargetTableID = 13
    AND AT.ProcessID IN (30, 31)
GROUP BY
    AT.PrimaryIDChanged 

Target is EF6. I have no code to share as yet

Answer 1

You can do it in Query Syntax like this:

var data =
    from at in context.AuditTrail
    where at.AuditTargetTableID == 13
       && new[]{ 30, 13 }.Contains(at.ProcessID)
    group at by at.PrimaryIDChanged into g
    select new {
        PID = g.Key,
        EventTypeID = g.Max(at => at.ProcessID),
        EventDate = g.Min(at => at.AuditDateTime),
    };

Note the into g, this allows you to do multiple aggregation functions on the whole group.