I recently had exactly the same problem on SQLAlchemy 0.8 where doing
something like "somestring" + Item.some_column would not result in a "||"
but in a "+" operator which sqlite could not handle. To note here in my
case: The "some_column" was the id, thus an integer. I'm not sure how
SQLAlchemy handles the operators exactly, but could this be a bug? Or is it
intended behaviour?
On Thursday, August 29, 2013 8:58:55 PM UTC+2, Gunnlaugur Briem wrote:
>
> I would have expected the SQLite dialect to know how to compile concat to
> || if that's the operator. But failing that, something more explicit like
> this ought to do the trick:
>
> from sqlalchemy.sql import literal_column
> literal_column("'+ '").op('||')(seconds.c.n).op('||')(literal_column("'
> seconds'"))
>
> Gulli
>
>
>
> On Thu, Aug 29, 2013 at 12:33 PM, Greg Yang <[email protected]<javascript:>
> > wrote:
>
>> I'm trying to get a series of datetimes using func.datetime. The format
>> of input is func.datetime(basetime, '+ NNN seconds'), which works nicely if
>> the shift applied is constant. However I need to add 10, 20, 30 seconds,
>> etc to this base time. So I want something like func.datetime(basetime,
>> concat('+', seconds.c.n, ' seconds')), but concat doesn't work for sqlite,
>> which concatenates using the '||' operator. Is there working method to
>> concat in sqlite?
>>
>> Failing that, is there another way to get at what I want with datetime
>> arithmetics?
>>
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