Select All columns for all tables in join + linq join

You could use the into clause, but it will not flatten it for you.

from CTLJCRJOB in CTRL_RUN_JOBs 
join CTLRFDSTM in CTRL_DATA_STREAMs 
on CTLJCRJOB.DATA_STREAM_ID equals CTLRFDSTM.DATA_STREAM_ID into ALLCOLUMNS
from entry in ALLCOLUMNS
select entry 

While you cant expand them to columns, you can simply return the entities. Eg:

select new { CTLJCRJOB, CTLRFDSTM }

If you need it flattened, then you will have to write out the mapping yourself, but will still be very trivial.

Another twist is

OutPutList = (from CTLJCRJOB in CTRL_RUN_JOBs 
              join CTLRFDSTM in CTRL_DATA_STREAMs 
                on CTLJCRJOB.DATA_STREAM_ID equals CTLRFDSTM.DATA_STREAM_ID
              select CTLJCRJOB).ToList();