How to translate SQL to C#

Question

I have a SQL query that looks like this:

SELECT
    a.Date,
    CASE
        WHEN a.Type = 'String 1' OR a.Type = 'String 2' 
            THEN 'foo'
            ELSE 'bar'
    END AS VisitType,
    DATEDIFF (d, (SELECT TOP 1 Date FROM dim.Date WHERE DateKey = a.StartDate), 
                 (SELECT TOP 1 Date FROM dim.Date WHERE DateKey = a.EndDate)) AS Duration

I am trying to convert it to a C# expression and so far I have something like this:

var allowedTypes = new[]{"String 1","String 2", "String 3", "String 4"}
var Data = from a in dbContext.Claim
where a.MemberId = memberId
&& a.StartDate > startDate
&& a.EndDate <= endDate
&& a.Type.Where(???t => allowedTypes.Contains(allowedTypes))  // This line I have issues with
select new
{
   Date = a.EndDate,
   VisitType = ???,
   VisitDuration = ???
}

I am having difficulty with the DateDiff concepts and doing a Contains like method with a string array. ALSO I have realized that the type of the dates are contained in a nullable int.

Thanks for all your advice so far~!

Answer 1

Try moving the conditional into the result:

select new
{
   Date = a.EndDate,
   VisitType = allowedTypes.Contains(a.Type) ? "foo" : "bar",
   VisitDuration = ???
}

Answer 2

var result = dbContext.Claims
    .Where (claim => claim.MemberId = memberId
                  && claim.StartDate > startDate
                  && claim.EndDate <= endDate
    .Select(claim => new
    {
        Date = claim.EndDate,
        VisitType = allowedTypes.Contains(claim.Type) ? "foo" : "bar",
        VisitDuration = claim.EndDate - claim.StartDate,
    });

In words: given values for memberId , startDate , endDate . From the table of Claims, keep only those Claims that have a value for property MemberId that equals memberId, a value for Property startDate that is higher than startDate, and a value for endDate that is smaller than endDate.

From every Claim in the sequence of remaining Claims, make one new object with three properties.

• Date is the EndDate of the Claim,
• Duration is the EndDate - StartDate of the claim
• If the VisityType of the Claim is in allowedTypes, then the value for property VisitType is "foo", else VisitType has a value of "bar"