XOR logical operator

[Nagib Abi Fadel]

Is there a XOR logical operator in Postgresql, or a
function for XOR ??

I only found in the docs a Binary XOR (#).

I need to do the following checkup:
(field1 is NULL XOR field2 is NULL XOR filed3 is NULL)

i can't right it like this:
(
(field1 is NUll or field2 is NUll)
and (field1 is NUll or field3 is NUll)
and (field2 is NUll or field3 is NUll)
)

But if i have alot of fields :
field1,field2,. ..,field5
.... this will take a hell of a time
I can write a function F1 that does the following:
if a field is NULL it will return 1
else it will return 0

then i can do:
(F1(field1) # F1(field2) # F1(field3) ...)
but i just wanted to see if XOR already exists ...

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[Pavel Stehule]

Hello,

PostgreSQL hasn't logical operator XOR. But You can find it in cookbook
http://www.brasileiro.net/postgres/c...41&format=long

Regards
Pavel

On Fri, 17 Oct 2003, Nagib Abi Fadel wrote:

Is there a XOR logical operator in Postgresql, or a
function for XOR ??

I only found in the docs a Binary XOR (#).

I need to do the following checkup:
(field1 is NULL XOR field2 is NULL XOR filed3 is NULL)

i can't right it like this:
(
(field1 is NUll or field2 is NUll)
and (field1 is NUll or field3 is NUll)
and (field2 is NUll or field3 is NUll)
)

But if i have alot of fields :
field1,field2,. ..,field5
... this will take a hell of a time
I can write a function F1 that does the following:
if a field is NULL it will return 1
else it will return 0

then i can do:
(F1(field1) # F1(field2) # F1(field3) ...)
but i just wanted to see if XOR already exists ...

_______________ _______________ ____
Do you Yahoo!?
The New Yahoo! Shopping - with improved product search
http://shopping.yahoo.com

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[Peter Childs]

On Fri, 17 Oct 2003, Nagib Abi Fadel wrote:

Is there a XOR logical operator in Postgresql, or a
function for XOR ??

I only found in the docs a Binary XOR (#).

I need to do the following checkup:
(field1 is NULL XOR field2 is NULL XOR filed3 is NULL)
Good idea. hmmm

CREATE FUNCTION xor(bool,bool) RETURNS bool AS '
SELECT ($1 AND NOT $2) OR (NOT $1 AND $2);
' LANGUAGE 'sql';

CREATE OPERATOR ~| (PROCEDURE='xor ',LEFTARG=bool, RIGHTARG=bool);

May not be all that neat but it does work so long as you use
brackets... I think improvements could be made. (10 minute job if that)

Peter Childs


i can't right it like this:
(
(field1 is NUll or field2 is NUll)
and (field1 is NUll or field3 is NUll)
and (field2 is NUll or field3 is NUll)
)

But if i have alot of fields :
field1,field2,. ..,field5
... this will take a hell of a time
I can write a function F1 that does the following:
if a field is NULL it will return 1
else it will return 0

then i can do:
(F1(field1) # F1(field2) # F1(field3) ...)
but i just wanted to see if XOR already exists ...

_______________ _______________ ____
Do you Yahoo!?
The New Yahoo! Shopping - with improved product search
http://shopping.yahoo.com

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[Manfred Koizar]

On Fri, 17 Oct 2003 01:04:48 -0700 (PDT), Nagib Abi Fadel
<na************ @yahoo.com> wrote:

Is there a XOR logical operator in Postgresql

Yes: !=

Servus
Manfred

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