sql - Update more rows than I expected - sql

Question

I'm trying to update a part of my table. If I do a select statement, I find 17 ocurrences, but when I update it, it updates 997 ocurrences. I only want to update the 17 ocurrences. This is my code:
update proc_try k set detail = (
select jobs from
(
with
a ( nameHost ) as (
select b.nameHost
from definition a ,schema.nodes b
where b.nameHost = a.idNode or b.nodeid=a.idNode
and nodetype not like 'R'
group by b.nameHost
having sum(1 + lengthb(nameJob)) - 1 > 4000
)
select nameHost, 'TOOLONG' as jobs
from a
UNION ALL
select p.nameHost, listagg(p.nameJob,',') within group (order by p.nameJob) as jobs
from
(
select distinct b.nameJob, a.nameHost
from definition b
right join schema.nodes a
on b.idNode in (a.nodeid,a.nameHost) and
b.application not like '#NOTINCLUDE'
where a.nameHost not in (select * from a) and nodetype not like 'R'
--b.application not like '#NOTINCLUDE'
) p
group by p.nameHost) random
where k.nameHost=random.nameHost);
Could you help me please?

Answer 1

You can generally convert a complex update into a merge:
merge into proc_try k
using
( select jobs
from ( with a(namehost) as
( select b.namehost
from definition a
join schema.nodes b
on b.namehost = a.idnode
or (b.nodeid = a.idnode and nodetype <> 'R')
group by b.namehost
having sum(1 + lengthb(namejob)) - 1 > 4000 )
select namehost
, 'TOOLONG' as jobs
from a
union all
select p.namehost
, listagg(p.namejob, ',') within group(order by p.namejob) as jobs
from ( select distinct
b.namejob, a.namehost
from schema.nodes a
left join definition b
on b.idnode in (a.nodeid, a.namehost)
and b.application not like '#NOTINCLUDE'
where a.namehost not in (select * from a)
and nodetype not like 'R'
) p
group by p.namehost
) random
) new_jobs
on (k.namehost = new_jobs.namehost)
when matched then update set k.detail = new_jobs.jobs;
This is untested as I don't have your tables or sample data.
Edit: Looks like we can simplify it a bit, to this:
merge into proc_try k
using
( with overlength (namehost) as
( select n.namehost
from definition d
join schema.nodes n
on n.namehost = d.idnode
or (n.nodeid = d.idnode and nodetype <> 'R')
group by n.namehost
having sum(1 + lengthb(n.namejob)) - 1 > 4000 )
select o.namehost, 'TOOLONG' as jobs
from overlength o
union all
select sd.namehost
, listagg(sd.namejob, ',') within group(order by sd.namejob) as jobs
from ( select distinct d.namejob, n.namehost
from schema.nodes n
left join definition d
on d.idnode in (n.nodeid, n.namehost)
and d.application not like '#NOTINCLUDE'
where n.namehost not in (select o.namehost from overlength o)
and n.nodetype not like 'R'
) sd
group by sd.namehost
) new_jobs
on (new_jobs.namehost = k.namehost)
when matched then update set k.detail = new_jobs.jobs;
I still can't see what
sum(1 + lengthb(namejob)) - 1
is meant to do, though. It looks like that could be simplified to
sum(lengthb(namejob))