Thread: two fields in subselect

I want to do this:

SELECT a, (select x,y,z from table2 where table1.a = table2.w), b, c
from table1;

But postgres complains:

ERROR:  Subselect must have only one field


How can I get around this?

Joseph Shraibman <jks@selectacast.net> writes:
> I want to do this:
> SELECT a, (select x,y,z from table2 where table1.a = table2.w), b, c
> from table1;
> But postgres complains:
> ERROR:  Subselect must have only one field

You haven't said what you expect to happen if table2 has zero or
multiple matches to any one table1.a value --- but if you want a
plain inner join you could do

SELECT a, x, y, z, b, c from table1, table2 where table1.a = table2.w;
        regards, tom lane

Tom Lane wrote:

> Joseph Shraibman <jks@selectacast.net> writes:
> > I want to do this:
> > SELECT a, (select x,y,z from table2 where table1.a = table2.w), b, c
> > from table1;
> > But postgres complains:
> > ERROR:  Subselect must have only one field
>
> You haven't said what you expect to happen if table2 has zero or
> multiple matches to any one table1.a value --- but if you want a
> plain inner join you could do
>
> SELECT a, x, y, z, b, c from table1, table2 where table1.a = table2.w;
>

I can't do that. I guess I should have elaborated some more. What I
really want to do is:

SELECT a, (select x,y,z from table2 where table1.a = table2.w), b,
(select x,y,z from table2 where table1.b = table2.w),  c from table1;

And table2.w is unique.