Query out only current checked out flag

I'm trying to create a query for searching for parts with no OPS and is not checked out so that we know that we have to create methods for that part. I'm getting all of the records that show up the ECOrev table, which apparently also has the historical data of what GroupID the part number was checked out under. So when I run my query, I get a line with the part number on the current GroupID and a line for any previous groupID's. I just want whether or not it is currently check out or not but I cannot figure out where to look to only grab the current record. Does anyone know how I can do this? Below is the code for the query if that helps. I'm sure it's a field somewhere, but I don't know where to look.

    [Part].[PartNum] as [Part_PartNum],
    [PartOpr].[OprSeq] as [PartOpr_OprSeq],
    [JobPart].[JobNum] as [JobPart_JobNum],
    [PartRev].[RevisionNum] as [PartRev_RevisionNum],
    [PartRev].[RevDescription] as [PartRev_RevDescription],
     when (PartOpr.OprSeq   is null )
     then 0
     else 1
 end) as [Calculated_isnull],
    [ECORev].[GroupID] as [ECORev_GroupID],
    [ECORev].[Approved] as [ECORev_Approved],
    [ECORev].[CheckedOut] as [ECORev_CheckedOut],
    [ECORev].[SysRevID] as [ECORev_SysRevID]
from Erp.Part as Part
left outer join Erp.PartOpr as PartOpr on
    Part.Company = PartOpr.Company
    Part.PartNum = PartOpr.PartNum

left outer join Erp.JobPart as JobPart on
    Part.PartNum = JobPart.PartNum
    Part.Company = JobPart.Company

left outer join Erp.PartRev as PartRev on
    Part.Company = PartRev.Company
    Part.PartNum = PartRev.PartNum

left outer join Erp.ECORev as ECORev on
    Part.Company = ECORev.Company
    Part.PartNum = ECORev.PartNum

 where (Part.TypeCode = 'm')
 order by  PartOpr.OprSeq ,  Part.PartNum Desc