no way... Oracle ALWAYS knows every value... it's a null comparation =
of
values, so, It's something like that...
select salary*12+commision
from employee;
so, the result will be:
salary*12+commision (If commision is NOT a null value)
or NULL (If commision has a null value...)
so, Oracle understands it like that:
" ok, if Salary=3D1000$
and Commision -> NULL
1000*12+"I_DONT_KNOW_THE_VALUE"=20
.... hmmmm...
... so, the result is: "I_DONT_KNOW_THE_VALUE" !! ;-))
It's just a sintax paradox (maybe a contradiction...)
It's just to tell you that the correct sintax is using "IS NULL" =
clause...
so, remember that if you want to make operations, you would have to use =
the
NVL function... ;-)
hope this would help...
Regards
Javier Morales - javier_at_infojobs.net
Administraci=F3n Bases de Datos Oracle - InfoJobs.net
Tel. +34 902 10 60 90 Ext. 2067
Fax. +34 (93) 580 56 60
=20
-----Mensaje original-----
De: GKor_at_rdw.nl [mailto:GKor_at_rdw.nl]
Enviado el: viernes 10 de noviembre de 2000 13:45
Para: Multiple recipients of list ORACLE-L
Asunto: RE: is null / =3D null query
why would you know those results in the first place ? you search =
something
but you are not sure what exactly ?
> -----Oorspronkelijk bericht-----
> Van: Javier Morales [SMTP:Javier_at_infojobs.net]
> Verzonden: 10-nov-00 13:20
> Aan: Multiple recipients of list ORACLE-L
> Onderwerp: RE: is null / =3D null query
>=20
> Null =3D I_DONT_KNOW_THE_VALUE
>=20
>=20
>=20
> SELECT COUNT(*) FROM WERK_ORDER WHERE RESULT_CODE_WO =3D NULL;
> 0
> 1 row selected.
>=20
> Oracle is saying something like that...
> "you asked me for counting the fields where the RESULT_CODE_WO field =
has
> an
> unknown value... but I know the values of EVERY RECORD... including =
the
> null values... (wich value is "I_DON'T_KNOW_THE_VALUE" ...)
>=20
>=20
>=20
>=20
> SQL> SELECT COUNT(*) FROM WERK_ORDER WHERE RESULT_CODE_WO IS NULL;
> 301
>=20
> 1 row selected.
>=20
> Oracle is saying something like that...
> "you asked me for counting the fields where the RESULT_CODE_WO field =
has a
> "I_DONT_KNOW_THE_VALUE" value... so I found 301 NULL values in that =
field"
>=20
>=20
>=20
> ... I hope you understand now!!... eheh... It's a bit complex at the
> begining of all, but It's just to get the trick !! ;-))
>=20
> Regards,
> Javier=20
> ---------------------------------------
> Javier Morales - javier_at_infojobs.net
> Administraci=F3n Bases de Datos Oracle - InfoJobs.net
> Tel. +34 902 10 60 90 Ext. 2067
> Fax. +34 (93) 580 56 60
> =20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
> -----Mensaje original-----
> De: Rao, Maheswara [mailto:Maheswara.Rao_at_Sungardp3.com]
> Enviado el: jueves 9 de noviembre de 2000 17:06
> Para: Multiple recipients of list ORACLE-L
> Asunto: RE: is null / =3D null query
>=20
>=20
> Gkor,
>=20
> When you want to compare null you use the clause IS NULL . =
Alternately, IS
> NOT NULL.
>=20
> As per your query, the second query is returning the result =
correctly.
> The
> first query returned zero rows because =3DNULL did not work.
>=20
> Now, please clarify, what exactly you mean by saying that you did not
> expect
> to get answer from the first query?
>=20
> Rao
>=20
> Maheswara.Rao_at_SunGardP3.com
>=20
> -----Original Message-----
>=20
> I have launched the following query in SQL*PLUS
>=20
> SQL> L
> 1* SELECT COUNT(*) FROM WERK_ORDER WHERE RESULT_CODE_WO =3D NULL;
> SQL> /
> 0
>=20
> 1 row selected.
>=20
> SQL> SELECT COUNT(*) FROM WERK_ORDER WHERE RESULT_CODE_WO IS NULL;
> 301
>=20
> 1 row selected.
>=20
> SQL>
>=20
> i did'nt expect to get answer on the first query anyone with an
> explanation
> or is this a undocumented feature ?
>=20
> thanks
>=20
> gkor_at_rdw.nl
> rdw the netherlands
> --
>=20
> --=20
> Please see the official ORACLE-L FAQ: http://www.orafaq.com
> --=20
> Author: Rao, Maheswara
> INET: Maheswara.Rao_at_Sungardp3.com
>=20
> Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
> San Diego, California -- Public Internet access / Mailing =
Lists
> --------------------------------------------------------------------
> To REMOVE yourself from this mailing list, send an E-Mail message
> to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
> the message BODY, include a line containing: UNSUB ORACLE-L
> (or the name of mailing list you want to be removed from). You may
> also send the HELP command for other information (like subscribing).
> --=20
> Please see the official ORACLE-L FAQ: http://www.orafaq.com
> --=20
> Author: Javier Morales
> INET: Javier_at_infojobs.net
>=20
> Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
> San Diego, California -- Public Internet access / Mailing =
Lists
> --------------------------------------------------------------------
> To REMOVE yourself from this mailing list, send an E-Mail message
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> also send the HELP command for other information (like subscribing).
--=20
Please see the official ORACLE-L FAQ:
http://www.orafaq.com
--=20
Author:=20
INET: GKor_at_rdw.nl
Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
San Diego, California -- Public Internet access / Mailing Lists
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Received on Fri Nov 10 2000 - 09:10:12 CST
