date

I have a table like this :
table books (name varchar , return_date date)

The field return_date is not initialized :
insert into books values (name1);
insert into books values (namex);

The field return_date is updated when the books is returned like this :

update books set return_date='10-06-1999' where name=xxx;

How can i select all the item where the return_date is not updated ?

a request like this :

select * from books where return_date='' ????

(actually i initialised the return_date with the values '01-01-0001')

thank you.

--
Roland Dubouloz BULL XS/BU
BULL SA mailto:Roland(dot)Dubouloz(at)bull(dot)net
1,Rue de Provence Phone :+33 (0)4 76 29 77 87
BP 208 Bullcom : 229-7787
38432 Echirolles CEDEX Office : A1-052
France Fax : +33 (0)4 76 29 70 02

Roland_DUBOULOZ ha scritto:

> I have a table like this :
> table books (name varchar , return_date date)
>
> The field return_date is not initialized :
> insert into books values (name1);
> insert into books values (namex);
>
> The field return_date is updated when the books is returned like this :
>
> update books set return_date='10-06-1999' where name=xxx;
>
> How can i select all the item where the return_date is not updated ?
>
> a request like this :
>
> select * from books where return_date='' ????
>

SELECT * FROM books WHERE return_date IS NULL;

>
> (actually i initialised the return_date with the values '01-01-0001')
>
> thank you.
>
> --
> Roland Dubouloz BULL XS/BU
> BULL SA mailto:Roland(dot)Dubouloz(at)bull(dot)net
> 1,Rue de Provence Phone :+33 (0)4 76 29 77 87
> BP 208 Bullcom : 229-7787
> 38432 Echirolles CEDEX Office : A1-052
> France Fax : +33 (0)4 76 29 70 02

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PostgreSQL 6.5.0 on i586-pc-linux-gnu, compiled by gcc 2.7.2.3
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