Thread: How to remove an item from integer array type
Hello Gurus,
Table A has integer[] column. I need to delete specific integer value from
that column.
f1 | f2
1 {100, 101, 102, 103}
2 {200, 300, 400}
I want to remove 101 from f2 and also preserve the order.
f1 | f2
1 {100, 102, 103}
2 {200, 300, 400}
I tried the following query and it did remove the 101 but it didn't
preserve the order.
update tableA set f2 = (select array_agg(X.id) from (select unnest(f2) id
except select 101 id) X) where f1 = 1;
What's the best way to do this?
Thank you,
Choon Park
2013/2/21 ChoonSoo Park <luispark@gmail.com>
>
> Hello Gurus,
>
> Table A has integer[] column. I need to delete specific integer value from that column.
>
> f1 | f2
> 1 {100, 101, 102, 103}
> 2 {200, 300, 400}
>
> I want to remove 101 from f2 and also preserve the order.
>
> f1 | f2
> 1 {100, 102, 103}
> 2 {200, 300, 400}
>
> I tried the following query and it did remove the 101 but it didn't preserve the order.
> update tableA set f2 = (select array_agg(X.id) from (select unnest(f2) id except select 101 id) X) where f1 = 1;
>
> What's the best way to do this?
Assuming you want to keep the values in numeric order, add an ORDER BY:
update tableA set f2 = (select array_agg(X.id) from (select unnest(f2)
id except select 101 id ORDER BY id) X) where f1 = 1;
HTH
Ian Barwick
Sorry,
It's not ordered by value. It's not sorted list unfortunately. It can be
'{100, 120, 102, 130, 104}'.
Do you have other suggestion?
Thank you,
Choon Park
On Wed, Feb 20, 2013 at 11:47 AM, Ian Lawrence Barwick <barwick@gmail.com>wrote:
> 2013/2/21 ChoonSoo Park <luispark@gmail.com>
> >
> > Hello Gurus,
> >
> > Table A has integer[] column. I need to delete specific integer value
> from that column.
> >
> > f1 | f2
> > 1 {100, 101, 102, 103}
> > 2 {200, 300, 400}
> >
> > I want to remove 101 from f2 and also preserve the order.
> >
> > f1 | f2
> > 1 {100, 102, 103}
> > 2 {200, 300, 400}
> >
> > I tried the following query and it did remove the 101 but it didn't
> preserve the order.
> > update tableA set f2 = (select array_agg(X.id) from (select unnest(f2)
> id except select 101 id) X) where f1 = 1;
> >
> > What's the best way to do this?
>
> Assuming you want to keep the values in numeric order, add an ORDER BY:
>
> update tableA set f2 = (select array_agg(X.id) from (select unnest(f2)
> id except select 101 id ORDER BY id) X) where f1 = 1;
>
> HTH
>
> Ian Barwick
>
It works!
Thank you,
Choon Park
On Wed, Feb 20, 2013 at 12:06 PM, Russell Keane <Russell.Keane@inps.co.uk>wrote:
> ** **
>
> >>Sorry,****
>
> >>** **
>
> >>It's not ordered by value. It's not sorted list unfortunately. It can
> be '{100, 120, 102, 130, 104}'.****
>
> >>** **
>
> >>Do you have other suggestion?****
>
> >>** **
>
> >>Thank you,****
>
> >>Choon Park****
>
> >** **
>
> >This should work:****
>
> >update a set f2 = (select array_agg(X.id) from (select f1, unnest(f2) id
> from a where f1 = 1 except select 1 f1, 101 id) X) where f1 = 1;****
>
> ** **
>
> And with the correct table name:****
>
> update tableA set f2 = (select array_agg(X.id) from (select f1, unnest(f2)
> id from tableA where f1 = 1 except select 1 f1, 101 id) X) where f1 = 1;**
> **
>
> ** **
>
> ** **
>
> ** **
>
> Regards,****
>
> ** **
>
> *Russell Keane***
>
> *INPS*****
>
> * *
>
> Tel: +44 (0)20 7501 7277****
>
> [image: cid:image001.jpg@01CDBE9B.11D013F0]****
>
> Follow us <https://twitter.com/INPSnews> on twitter | visit www.inps.co.uk
> ****
>
> ** **
>
> ** **
>
> ** **
>
2013/2/21 Russell Keane <Russell.Keane@inps.co.uk>
>
>
>
> >>Sorry,
>
> >>
>
> >>It's not ordered by value. It's not sorted list unfortunately. It can be '{100, 120, 102, 130, 104}'.
>
> >>
>
> >>Do you have other suggestion?
>
> >>
>
> >>Thank you,
>
> >>Choon Park
>
> >
>
> >This should work:
>
> >update a set f2 = (select array_agg(X.id) from (select f1, unnest(f2) id from a where f1 = 1 except select 1 f1, 101
id)X) where f1 = 1;
>
>
>
> And with the correct table name:
>
> update tableA set f2 = (select array_agg(X.id) from (select f1, unnest(f2) id from tableA where f1 = 1 except select
1f1, 101 id) X) where f1 = 1;
I don't think that will work, except accidentally;
testdb=# CREATE TABLE tablea(f1 int, f2 int[]);
CREATE TABLE
testdb=# INSERT INTO tablea values(1, '{100,101,102,103,99,104,22}');
INSERT 0 1
testdb=# BEGIN ;
BEGIN
testdb=*# update tableA set f2 = (select array_agg(X.id) from (select
f1, unnest(f2) id from tablea where f1 = 1 except select 1 f1, 101 id)
x) where f1=1;
UPDATE 1
testdb=*# SELECT * from tablea ;
f1 | f2
----+-------------------------
1 | {100,22,103,99,104,102}
(1 row)
testdb=*# ROLLBACK ;
ROLLBACK
Moving the exclusion operation up a level seems to do the trick:
testdb=# BEGIN ;
BEGIN
testdb=*# update tableA set f2 = (select array_agg(X.id) from (select
f1, unnest(f2) id from tablea where f1 = 1) x WHERE x.id != 101) where
f1=1;
UPDATE 1
testdb=*# SELECT * from tablea ;
f1 | f2
----+-------------------------
1 | {100,102,103,99,104,22}
(1 row)
(It's a bit late where I am so I might be overlooking something)
Ian Barwick
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On Feb 20, 2013, at 17:51, ChoonSoo Park <luispark@gmail.com> wrote:
> Sorry,
>=20
> It's not ordered by value. It's not sorted list unfortunately. It can =
be '{100, 120, 102, 130, 104}'.
Are you saying it's an unordered list for which the order matters? That =
seems a bit peculiar.
What would probably work is to split the array around the value to =
remove, and merge those arrays again.
Something like this:
=3D> select (ARRAY[100, 101, 102, 103, 104])[1:2] || (ARRAY[100, 101, =
102, 103, 104])[4:5];
?column?
-------------------
{100,101,103,104}
(1 row)=20
=20
Alban Hertroys
--
If you can't see the forest for the trees,
cut the trees and you'll find there is no forest.