Using OPENQUERY with a table created on the fly

Question

I have a four-part linked server query that LEFT OUTER JOINs a table created on the fly using UNION ALL, something along these lines:

SELECT t.column1, rlt.s6, SUM(t.column3) column3
FROM Linked_server.database.schema.table t
    LEFT OUTER JOIN (
        SELECT 1 AS s7, 15 AS s6
        UNION ALL SELECT 3, 1
        UNION ALL SELECT 20, 16
    ) rlt ON (rlt.s7 = t.column2)

That works fine. However, when I'm running that same query with OPENQUERY function, like that:

SELECT * FROM OPENQUERY(Linked_server, '
    SELECT t.column1, rlt.s6, SUM(t.column3) column3
    FROM database.schema.table t
        LEFT OUTER JOIN (
            SELECT 1 AS s7, 15 AS s6
            UNION ALL SELECT 3, 1
            UNION ALL SELECT 20, 16
        ) rlt ON (rlt.s7 = t.column2)
')

, LEFT OUTER JOIN fails and s6 column only contains NULLs. I understand I could rewrite the query #2 to make it work, but I am curious why it doesn't work the way it is written? Is it because there is some limitation on OPENQUERY I am unaware of?

Answer 1

Haven't been able to reproduce this on my machine... The only difference is in the sort order of two queries. Maybe it just seems visually that result sets differ because of a different sort order. Try adding ORDER BY rlt.s6 DESC in both queries and then run them, this should give you result sets with same records arranged in same order.