Your biggest problem is that you are using Functions against columns in the where of the subquery which will cause a table scan. You should first look at how you can eliminate that. Can you give us the definition of the table, some test data, and what you are trying to accomplish with the query? Can you convert it to a stored procedure where we can use table variables/temp tables?

This may be what you want:

[font="Courier New"]SELECT

    F.*

FROM

    xxxxflow F JOIN

    (SELECT

        MAX(mstr_ordid) AS max_ord_id,

        Ord_Num,

         CONVERT(VARCHAR(10),b.date,101) AS date_string

    FROM

         xxxflow) B ON

        f.Ord_Num = B.Ord_Num AND

        CONVERT(VARCHAR(10),f.date_time,101) = B.date_string AND

        F.mstr_ordid = B.max_ord_id

[/font]