On Thu, Apr 20, 2017 at 3:56 PM, jonathan vanasco <postg...@2xlp.com> wrote:
> thanks all! > > On Apr 20, 2017, at 6:42 PM, David G. Johnston wrote: > > ​Subqueries can see all columns of the parent. When the subquery actually > uses one of them it is called a "correlated subquery". > > > i thought a correlated subquery had to note that table/alias, not a raw > column. I guess i've just been adhering to good form. > > > On Apr 20, 2017, at 6:43 PM, Tom Lane wrote: > > Cautious SQL programmers qualify all references inside sub-selects to > avoid getting caught by this accidentally. > > > is there a syntax to qualify a reference to lock a subquery to the current > scope (disable looking at the parents)? that's how I got caught on this by > accident. > Like Tom said, "qualify all references": ...(SELECT example_a__rollup.bar_id FROM example_a__rollup)... Or shortened with alises: ...(SELECT x.bar_id FROM example_a__rollup x)... Cheers, Steve
