|
|
Posted by Robert Klemme on 08/08/06 15:16
On 08.08.2006 16:31, jason.langdale@gmail.com wrote:
> I have 3 tables I want to use in a view. Table A has field 1,2,3,4,5
> and table B has field 1,2,3,4,5. I want to do a union on these. (I have
> done so successfully if I stop here) I also want to join table C which
> has field 1,6,7,8,9. I would like to join on field 1 and bring in the
> other fields. I can join table C to A or B. I can union table A and B
> but I do not know how to both union A and B then join C. Can someone
> please help me? Thanks in advance.
What stops you from joining twice? Can't you just do
select 1,2,3,4,5,6,7,8,9
from tab_a, tab_c
where tab_a.1 = tab_c.1
union all
select 1,2,3,4,5
from tab_b, tab_c
where tab_b.1 = tab_c.1
Alternatively
select 1,2,3,4,5,6,7,8,9
from (
select 1,2,3,4,5
from tab_a
union all
select 1,2,3,4,5
from tab_b
) unioned, tab_c
where unioned.1 = tab_c.1
....
Of course you can also create a view for the union and then another one
for the join - this might be more easier to manage and handle. My guess
would be that the first approach is more efficient but this depends of
course on your data.
HTH
robert
Navigation:
[Reply to this message]
|