select cd from loc 

This will return one row per record.

DECLARE @something NVARCHAR(10)
DECLARE @together NVARCHAR(max) = ''
DECLARE @delimiter NVARCHAR(5) = ', '
DECLARE Alist CURSOR FOR 
  SELECT cd FROM loc -- <<<< put your query here.

OPEN Alist

FETCH NEXT FROM Alist INTO @something

WHILE @@FETCH_STATUS = 0
BEGIN

  SET @together = @together + @something 
  FETCH NEXT FROM Alist INTO @something
  IF @@FETCH_STATUS = 0 SET @together = @together + @delimiter  -- Do not add last delimiter if at end of record set.

END
SELECT @together
CLOSE Alist
DEALLOCATE Alist

This is a cursor that will save each row into a variable and separate it with commas.