Different results in sqlfiddle.com 5.5.30 and MariaDB 5.5.31

Question

sqlfiddle: http://sqlfiddle.com/#!2/9a8b3/1

Taking the structure and data and query from the fiddle, importing into my MariaDB 5.5.31, I get different results:

s

Answer 1

Afraid I don't have MariaDB to hand, but could you try the following just to see how the user variables are output:-

SELECT  *
FROM test_golf_player p
LEFT JOIN 
(
    SELECT pid, leaguepoints, @Sequence:=IF(@PrevPid = pid, @Sequence + 1, 0) AS aSequence, @PrevPid := pid
    FROM
    (
        SELECT pid, leaguepoints
        FROM test_golf_card 
        ORDER BY pid, leaguepoints DESC
    ) Sub1
    CROSS JOIN (SELECT @PrevPid := 0, @Sequence := 0) Sub2
) gC
ON p.pid = gC.pid 
ORDER BY p.name DESC 

EDIT - Doing a bit of investigation looking at your results it seems that MariaDB has ignored the ORDER BY in the sub query. Hence the sequence number is in a random order, and also resets when the pid changes (which it does randomly due to the order not being fixed). Bit of a google and it seems this is a deliberate feature of MariaDB. The SQL standard defines a table as an unordered set of rows, and a sub select is treated as a table hence the order by is ignored - https://kb.askmonty.org/en/why-is-order-by-in-a-from-subquery-ignored/ .

It is a bit of a disadvantage. Not sure there is a work around as I can't think of one at the moment. For the original problem that this was to deal with I think it would be necessary to use correlated sub selects which would probably not be efficient.