Re: Select from dual?

[Jan Dvorak]

Hi,

MySQL lets you do a select without any tables,
i.e., without the from-clause.
So,

select 3;

returns one row, one column, value 3. 

To put a value into a variable (you mean the @a -style variables?),
you can either

select @a := 3;

or

set @a := 3;


And yes, if you want to do it the Oracle way,
why not just define a table called DUAL and put one row in it?

create table DUAL ( ID tinyint unsigned not null primary key ) max_rows=1;
insert into DUAL values ( 1 );

Hope this helps.


Jan



"M. A. Ould-Beddi" wrote:
> 
> I know that in Oracle it is possible to select a number
> from DUAL and put it in a variable. Is it possible
> In mysql? and how?
> 
> Thanks
> 
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AW: Antwort: Select from dual?

[Stephan Skusa]

DUAL is a dummy table in oracle ... !

In mysql you have two way to set variables:

1. set them directly via SET @variable={ integer expression | real
expression | string expression }[,@variable= ...].
2. or do something like select @variable:={ integer expression | real
expression | string expression }

you can read it out in the manual:
http://www.mysql.com/documentation/mysql/bychapter/manual_toc.html#Variables

> -Ursprungliche Nachricht-
> Von: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]]
> Gesendet: Donnerstag, 1. Marz 2001 10:54
> An: M. A. Ould-Beddi
> Cc: [EMAIL PROTECTED]
> Betreff: Antwort: Select from dual?
>
>
>
> On 01.03.2001 10:46:33 M. A. Ould-Beddi wrote:
>
> > I know that in Oracle it is possible to select a number
> > from DUAL and put it in a variable. Is it possible
>
> ??? What's DUAL?
>
>
>
> -
> Before posting, please check:
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>
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>


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Antwort: Select from dual?

[alexander . skwar]

On 01.03.2001 10:46:33 M. A. Ould-Beddi wrote:

> I know that in Oracle it is possible to select a number
> from DUAL and put it in a variable. Is it possible

??? What's DUAL?



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Select from dual?

[M. A. Ould-Beddi]

I know that in Oracle it is possible to select a number
from DUAL and put it in a variable. Is it possible
In mysql? and how?

Thanks


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