Ludwig Kniprath napisal 24.10.2008 11:45:
Join-table
mn_2_r_id mn_2_c_id
1 1
1 2
1 3
1 4
2 1
3 2
3 5
4 3
...
(in real database this relation is an gis-relation with thousands of
rivers and countries, related by
In article <[EMAIL PROTECTED]>,
Ludwig Kniprath <[EMAIL PROTECTED]> writes:
> Dear list,
> I have to solve a simple Problem, explained below with some sample-Data.
> A typical M:N-constellation, rivers in one table, communities in the
> other table, m:n-join-informations (which river is running i
On Fri, Oct 24, 2008 at 03:05:33PM +0200, Albe Laurenz wrote:
> Ludwig Kniprath wrote:
> > I want to know, which river is running through communities
> > 1,2,3 *and* 4?
> > You can see the solution by just looking at the data above (only
> > "river_1" is running through all these countries), but
hi,
try
select
r.*
from
rivers r
join jointable j1 on r.r_id=j1.mn_2_r_id join communities c1 on
j1.mn_2_c_id=c1.c_id and c1.C_Name='community_1'
join jointable j2 on r.r_id=j2.mn_2_r_id join communities c2 on
j2.mn_2_c_id=c2.c_id and c2.C_Name='community_2'
join jointable j3 on
Ludwig Kniprath wrote:
> A typical M:N-constellation, rivers in one table, communities in the
> other table, m:n-join-informations (which river is running in which
> community) in a third table.
>
> Table rivers:
> R_ID R_Name
> 1 river_1
> 2 river_2
> 3 river_3
> 4 river_4
> 5
Dear list,
I have to solve a simple Problem, explained below with some sample-Data.
A typical M:N-constellation, rivers in one table, communities in the
other table, m:n-join-informations (which river is running in which
community) in a third table.
Table rivers:
R_ID R_Name
1 river_1
2
