Is there any "FULL OUTER JOIN" in while select in AX2012

I am a new user in AX2012.

My while select statement is

    while select tableA
      outer join tableB
           where tableA.ItemId == tableB.ItemId
              && tableA.InventColorId == tableB.InventColorId
              && tableA.InventSizeId == tableB.InventSizeId

there are 316 records comes out.

when I use sql in sql server

SELECT *
FROM tableA ctt
FULL OUTER JOIN tableB tgt
ON ctt.itemid = tgt.itemid
AND ctt.inventcolorid = tgt.inventcolorid
AND ctt.inventsizeid = tgt.inventsizeid

there are 317 records come out.

The difference is a record in tableB cannot come out in the while select statement. Please tell me how get all of the records in tableA and tableB with out join in while select statement. Thank you.