Re: How to eliminate extra "NOT EXISTS"-query here? - Mailing list pgsql-general

On Sat, Nov 25, 2023 at 5:53 PM hector vass <hector.vass@gmail.com> wrote:

Not sure you need to use array why not simple table joins, so a table with your criteria x y z t joined to stuff to give you candidates that do match, then left join with coalesce to add the 'd' 

select

--a.id,b.test_id,

coalesce(a.id,b.test_id) as finalresult

from test a

left join (

select

test_id

from stuff a

inner join (values ('x'),('y'),('z'),('t')) b (v) using(v)

group by 1

)b on(a.id=b.test_id);

Hi Hector. Hopefully this is not a stupid question...

How is that equivalent from the `NOT ARRAY ... <@ ...` though?

The inner-join-distinct above will return test_id's on any match, but you

can't know if all array values are matches. Which is different from

> Is the first array contained by the second

from the <@ operator, no?

I'm unfamiliar with these operators, so am I missing something?

Just trying to understand the logic here. Thanks, --DD