Re: join two tables without a key

On 03/04/2010 12:32, Dino Vliet wrote:
> --- On Sat, 4/3/10, Raymond O'Donnell <rod(at)iol(dot)ie> wrote:
> On 03/04/2010 11:16, Dino Vliet wrote:
>
>> Hi postgresql list, If I have two tables with the same number of rows
>> but different columns and I want to create one table out of them what
>> would be the way to do that in postgresql?
>>
>> Table A has N number of rows and columns X,Y,Z and Table B has N
>> number of rows and P,Q,R as columns. None of the tables have a
>> column which can be used as a key.
>>
>> The resulting table should have N number of rows and X,Y,Z,P,Q,R as
>> columns.
>
> How do the rows in the tables relate to each other? You need to decide
> first how you match the rows in A and B.

> they don' t. It' s pure randomly generated data.

In that case, how about getting the cartesian product of the two tables,
and then LIMITing the result to N rows? - Something like this:

select
a.x, a.y, a.z,
b.p, b.q, b.r
from
a, b
limit N;

....substituting your value of N. It'll be slow if there are a lot of
rows in A and B, mind.

Ray.