Joining multiple tables

[Vetle]

Hi,

I'm reading the documentation on SQL Alchemy, but perhaps I'm missing
something here ... I need to join multiple tables, table1 with table2
and table1 again.

So, in SQL, I'd do something like:

select * from t1 join t2 on t1.b = t2.c join t1 t3 on t1.a = t3.a;

Yeah, it doesn't make much sense, but it's an example. Any ideas on
how I'd do that in SA? I'm having trouble figuring it out. :)

[Michael Bayer]

hi Vetle -

the Table object supports a join() method, which can be called in a
chain, i.e.

table1.join(table2).join(table3)...

if you need to specify the "ON" part of the join, its the second
argument to join() (below illustrated with two joins back to table1):

table1.join(table2, table1.c.id==table2.c.someid).join(table3,
table1.c.id==table3.c.id)

hope this helps...

[Vetle Roeim]

Yes thanks, it helped a little bit. I realized I could to this inside
from_obj = [ ... ]. That, in addition to using table aliases.

I ended up with something like:
t1_2 = t1.alias('t1_2')
select([t1, t1.c.a .... ],
from_obj = [t1.join(t1_2, t1.c.a = t1_2.c.b).join(.....)]

It was kinda complicated, and the schema could have been designed a
little differently, but I got it working at last. ;)

--
Vetle Roeim