Re: [opendbx] Bug with Sqlite3, UNION and NULL?

[Mariano M. P. <mar...@gm...>]

Thanks Norbert for the answer. So we will see what we can do.
Best regards,

On Thu, Jun 16, 2011 at 10:58 PM, Norbert Sendetzky <
no...@li...> wrote:

> Hi Mariano
>
> > That fails with something...we have tried to isolate the problem to the
> > minimum. To reproduce do these steps:
> >
> > 'Create table test (c1 int NULL, c2 int NULL)'.
> >   'insert into test values(1, NULL)'.
> > 'insert into test values(NULL, 3)'.
> > 'select * from (select t1.c1, null t3 from test t1 UNION ALL select NULL
> t3,
> > t2.c2 from test t2)'.
> >
> > Then after, fetch all rows. Then, if you take the last row (number 4),
> which
> > has (NULL, '3'), and you try to ask the type of position 2  you get an
> > UKNOWN instead of type for the integer.
> >
> > Is this a bug? if true, where? OpenDBX? slite3 library? sqlite3 database?
>
> Not a bug, it's a feature ;-)
>
> SQLite uses an own datatype for NULL values which is not known in SQL
> standard (http://sqlite.org/c3ref/c_blob.html). The problem is that
> SQLite changes the datatype of the column in the result set from INT to
> NULL if the value is NULL in the current row. There's no known
> workaround for this.
>
>
> Norbert
>
>
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-- 
Mariano
http://marianopeck.wordpress.com