upsert and update filtering
Hi
create table dimc1
(
col1 integer not null,
col2 char(10),
primary key (col1)
);
create table dimc2
(
col1 integer not null,
col2 char(10),
primary key (col1)
);
testdb=# select * from dimc1 order by 1;
col1 | col2
------+------------
111 | foo111
112 | foo112
(2 rows)
testdb=# select * from dimc2 order by 1;
col1 | col2
------+------------
111 | foo111
112 | foo122
211 | foo211
In general it is my understanding it gows like this
insert into dimc1 select * from dimc2
on conflict (col1) do update
SET
col2 = EXCLUDED.col2
;
insert into dimc1 select * from dimc2
on conflict (col1) do update
SET
col2 = EXCLUDED.col2 returning *
;
So far so good
But what if in the conflict situation I want to performa the update ONLY if the record is different. The update seems to happen no matter what
In other words is there anyway I can filter the update to happen (based on the sample date) only for 112 since col2 is different ?
testdb=# select * from dimc1 order by 1;
col1 | col2
------+------------
112 | foo112
testdb=# select * from dimc2 order by 1;
col1 | col2
------+------------
112 | foo122
Thanks
Armand
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armand pirvu <armand.pirvu@gmail.com> wrote:
But what if in the conflict situation I want to performa the update ONLY if the record is different. The update seems to happen no matter what
In other words is there anyway I can filter the update to happen (based on the sample date) only for 112 since col2 is different ?
That's quite possible. An ON CONFLICT's UPDATE accepts a WHERE clause,
which can reference both existing and excluded tuples. That WHERE clause
can back out of the UPDATE based on whatever criteria you like.
--
Peter Geoghegan
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aaaa
That's because the access on this case is done to the existing row using the table's name / alias , and to the rows that we attempt to insert using the excluded
Thank you Peter
Armand
On Jul 31, 2017, at 4:31 PM, Peter Geoghegan <pg@bowt.ie> wrote:
armand pirvu <armand.pirvu@gmail.com> wrote:
But what if in the conflict situation I want to performa the update ONLY if the record is different. The update seems to happen no matter what
In other words is there anyway I can filter the update to happen (based on the sample date) only for 112 since col2 is different ?That's quite possible. An ON CONFLICT's UPDATE accepts a WHERE clause,
which can reference both existing and excluded tuples. That WHERE clause
can back out of the UPDATE based on whatever criteria you like.--
Peter Geoghegan
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