Re: "could not determine data type of parameter" with timestamp

Yes, ps.setNull(1, Types.TIMESTAMP) works.
But, once again, with the way my application works, when I bind the
parameters, the query is already built. So, if my parameter is null, I have
no way to guess its type.
I tried ps.setNull(1, Types.VARCHAR) as a fallback, and it works with a
condition like "where ? is null". It does not work with a condition like "where
birth_date > ?".
Maybe we could parse the query to use ps.setNull(1, Types.VARCHAR) when we
have something like "? is null" (and a null bound parameter), but it seems
to be weak (and a little bit dirty).
Why is the driver not able to ignore the parameter type when we just want
to compare it to null?

Rémi.

Le mer. 6 déc. 2017 à 01:58, Dave Cramer <pg(at)fastcrypt(dot)com> a écrit :

> So ps.setNull(1, Types.TIMESTAMP);
>
> Doesn't work ?
>
> Dave Cramer
>
> davec(at)postgresintl(dot)com
> www.postgresintl.com
>
> On 5 December 2017 at 15:42, David G. Johnston <david(dot)g(dot)johnston(at)gmail(dot)com
> > wrote:
>
>> On Tue, Dec 5, 2017 at 8:11 AM, Rémi Aubel <remi(dot)aubel(at)gmail(dot)com> wrote:
>>
>>> Hello,
>>>
>>> I know my problem has already been answered in this list (
>>> https://www.postgresql.org/message-id/CA%2BxsaB0EMDaNek0Oky9c17_8UX3-epWVP11%2BvTNgrAPoY2s9FA%40mail.gmail.com),
>>> but it was a long time ago and I would like to know if any other solution
>>> exists now.
>>>
>>
>> ​Not that I am aware.​
>>
>>
>>> But this workaround is not really useful for me, because my application
>>> uses generated (dynamic) queries and targets multiple database types (not
>>> only PosgreSQL). So, when I know the targeted database, I do not know my
>>> parameter types anymore.
>>>
>>
>> ​I'd probably perform the null test in Java and pass the true/false
>> boolean result along to the query:
>>
>> SELECT * FROM my_table WHERE ?::bool;
>> ps.setBoolean(1, tsvar = null); //my Java is rusty but you get the idea.
>>
>> That should work in any database.
>>
>> David J.
>> ​
>>
>
> --