2008/10/29 Gaetan de Menten <[EMAIL PROTECTED]>: > > On Tue, Oct 28, 2008 at 11:53 AM, Alex Marandon <[EMAIL PROTECTED]> wrote: >> >> 2008/10/28 Gaetan de Menten <[EMAIL PROTECTED]>: >>> >>> On Mon, Oct 27, 2008 at 6:52 PM, Alex Marandon <[EMAIL PROTECTED]> wrote: >>> >>>> Just a quick word to mention that I've just posted a (ridiculously >>>> simple) patch at http://elixir.ematia.de/trac/ticket/34 >>> >>> Thanks. But this introduces an extra query for all DB, which I'd >>> prefer to avoid. Could you test if it works with "as_scalar" instead? >> >> Using as_scalar leads to generating this type of subquery that MySQL >> doesn't support. I've tested it and unfortunately it doesn't work. >> >> The problem with MySQL is documented at >> http://dev.mysql.com/doc/refman/5.0/en/subquery-errors.html "You can >> use a subquery for assignment within an UPDATE statement because >> subqueries are legal in UPDATE and DELETE statements as well as in >> SELECT statements. However, you cannot use the same table (in this >> case, table t1) for both the subquery's FROM clause and the update >> target." >> >> The error message returned by MySQL is: >> OperationalError: (OperationalError) (1093, "You can't specify target >> table 'todos' for update in FROM clause") u'UPDATE todos SET >> position=(SELECT max(todos.position) + %s AS anon_1 \nFROM todos >> \nWHERE todos.owner_id = %s) WHERE todos.id = %s' [1, 1L, 3L] > > Wouldn't it be possible to use an alias or something like that to > workaround the issue?
I'm not too sure what you have in mind. What about testing which database engine is in use and do the extra query only for the unfortunate MySQL users? Hum, that's ugly too. Well, since acts_as_list is going to be deprecated anyway, having the patch in the bug tracker is probably enough. Those who need it can apply it. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "SQLElixir" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlelixir?hl=en -~----------~----~----~----~------~----~------~--~---
