On Mar 2, 1:21 pm, "Valentin Minzatu" <valentinminz..._at_yahoo.com>
wrote:
> On Mar 2, 11:07 am, mer..._at_gmx.net (Tobias Merler) wrote:
>
>
>
>
>
> > Assume I join two tables.
> > Both of these tables contain a column with name "col1". This column ist not he primary key.
> > However this column contains different values which value is taken ?
>
> > Lets see the following example:
>
> > Select *
> > FROM tablea a, tableb b
> > Where a.id = b.id
>
> > tablea:
>
> > id col1 col2
>
> > 1 aaa ddd
> > 2 bbb eee
> > 3 ccc fff
>
> > tableb:
>
> > id col1 col3
>
> > 1 zzz uuu
> > 2 xxx vvv
> > 3 yyy www
>
> > The result table will look like:
>
> > id col1 col2 col3
>
> > 1 ??? ddd uuu
> > 2 ??? eee vvv
> > 3 ??? fff www
>
> > Which values will be for the questions marks ?
>
> > Ok, I know the data model is not perfect and the two tables could be merged.
> > But keep in mind that the sample is only a simplified version of a more complex
> > SQL statement. So lets concentrate on my question.
>
> > Thank you
>
> > Toby
>
> The query as you wrote it will return 6 columns because you used *. If
> you only want 4 columns, you will have to replace * with the fully
> qualified names of the 4 columns.- Hide quoted text -
>
> - Show quoted text -
Well, something weird is happening with this post ...
Received on Fri Mar 02 2007 - 12:45:35 CST
