Re: [SQL] regarding join
given this.
create table AA (id serial,name varchar(15));
create table BB (id serial,name varchar(15));
insert into AA (name) values ('1243f');
insert into AA (name) values ('asdfef');
insert into AA (name) values ('fdbsfd');
insert into AA (name) values ('btgrt');
insert into AA (name) values ('crregsewf');
insert into AA (name) values ('xedrgeef');
insert into BB (name) values ('243f');
insert into BB (name) values ('sdfef');
insert into BB (name) values ('dbsfd');
insert into BB (name) values ('tgrt');
insert into BB (name) values ('rregsewf');
insert into BB (name) values ('edrgeef');
you could try: (if you just need the one column "name")
select name from AA union select name from BB order by name;
a real nice way to go about this is:
create table CC (id serial,name varchar(15));
create table AA() inherits(CC);
create table BB() inherits(CC);
insert into AA (name) values ('1243f');
insert into AA (name) values ('asdfef');
insert into AA (name) values ('fdbsfd');
insert into AA (name) values ('btgrt');
insert into AA (name) values ('crregsewf');
insert into AA (name) values ('xedrgeef');
insert into BB (name) values ('243f');
insert into BB (name) values ('sdfef');
insert into BB (name) values ('dbsfd');
insert into BB (name) values ('tgrt');
insert into BB (name) values ('rregsewf');
insert into BB (name) values ('edrgeef');
=> select * from AA;
id | name
+---
1 | 1243f
2 | asdfef
3 | fdbsfd
4 | btgrt
5 | crregsewf
6 | xedrgeef
(6 rows)
=> select * from BB;
id | name
+--
7 | 243f
8 | sdfef
9 | dbsfd
10 | tgrt
11 | rregsewf
12 | edrgeef
(6 rows)
=> select * from CC order by name;
id | name
+---
1 | 1243f
7 | 243f
2 | asdfef
4 | btgrt
5 | crregsewf
9 | dbsfd
12 | edrgeef
3 | fdbsfd
11 | rregsewf
8 | sdfef
10 | tgrt
6 | xedrgeef
(12 rows)
by best regards,
Stefan
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Am Samstag, 25. März 2006 07:36 schrieb AKHILESH GUPTA:
> hi all,
> below I have created two tables in pgsql with field name as 'name' and 'id'
> as their datatype 'varchar(15)' and 'integer'.
>
> One of the table is:->
> chemical=> select * from test1;
> name | id
> ---+
> akhil | 1
> b | 2
> c | 3
> d | 4
> e | 5
> f | 6
> (6 rows)
>
> Another table is:->
> chemical=> select * from test3;
> name | id
> --+
> ab | 1
> cd | 2
> ef | 3
> gh | 4
> (4 rows)
>
> i want the output as:->
> name | id
> ---+
> akhil | 1 -from test1 table
> ab | 1--from test2 table
> b | 2-from test1 table
> cd | 2--from test2 table
> c | 3-from test1 table
> ef | 3--from test2 table
> d | 4-from test1 table
> gh | 4--from test2 table
> e | 5-from test1 table
> f | 6-from test1 table
>
> i have tried all the joins but it makes different fields for different
> tables.
> is there any way out for this kind of output??
> (plz reply asap)urgent.
>
> THANKS IN ADVANCE
>
> --
> Thanks & Regards,
> Akhilesh
> S/W Trainee (EDP),
> NUCHEM Pvt. Ltd.,
> Faridabad(Haryana)
> GSM:-(+919891606064)
>
> "FAILURES CAN BE FORGIVEN BUT AIMING LOW IS A CRIME"
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Re: [SQL] Index on nullable column
> > Is an index on a nullable column useful for retrieving rows having that > > column null? > > Nope, because IS NULL isn't an indexable operator. > > You can make an end-run around that with a partial index, eg > > create index fooi on foo(f1) where f1 is null > > This can be used to satisfy queries using "where f1 is null", but it's > not any good for any other purpose. > > If you often do "where f1 is null and something-about-f2", > you might get better mileage with > > create index fooi on foo(f2) where f1 is null > > but it's still a very specialized index. > Thanks Tom. I will use such an index even if it's very specialized; OLAP world is somewhat full of specialized index anyway... :-) -- Daniel ---(end of broadcast)--- TIP 6: explain analyze is your friend
Re: [SQL] Expressing a result set as an array (and vice versa)?
On Thu, 23 Mar 2006 11:44:32 -0800 Don Maier <[EMAIL PROTECTED]> threw this fish to the penguins: > Is it possible to construct an array from an appropriate select > expression that generates a result set of unknown cardinality? > To focus on the simple case: Is it possible to construct a one- > dimensional array from a select of a single column in a table with an > unknown number of rows? select array(select some_int_field from my_table where something); produces an array of integers. No user defined function is required. > Conversely, is it possible to construct a (single column) result set > from a select expression on a one-dimensional array with an unknown > number of elements? Not so easy without a custom function. > Thanks for any hints! > > Regards, > Don Maier > > > > ---(end of broadcast)--- > TIP 1: if posting/reading through Usenet, please send an appropriate >subscribe-nomail command to [EMAIL PROTECTED] so that your >message can get through to the mailing list cleanly > -- "Are the gods not just?" "Oh no, child. What would become of us if they were?" (CSL) ---(end of broadcast)--- TIP 5: don't forget to increase your free space map settings
Re: [SQL] Expressing a result set as an array (and vice versa)?
On Mar 25 10:11, george young wrote:
> On Mar 23 11:44, Don Maier <[EMAIL PROTECTED]> wrote:
> > Conversely, is it possible to construct a (single column) result set
> > from a select expression on a one-dimensional array with an unknown
> > number of elements?
>
> Not so easy without a custom function.
But not that hard:
test=> SELECT id, val FROM t_arr;
id | val
+---
1 | {1,2,3}
2 | {4,5,6}
3 | {7,8,9}
4 | {10,11,12,13}
(4 rows)
--
-- First Way
--
test=> SELECT id, val[s.i]
test-> FROM t_arr
test-> LEFT OUTER JOIN
test-> (SELECT g.s
test(> FROM generate_series(1, (SELECT max(array_upper(val, 1)) FROM
t_arr)) AS g(s)
test(> ) AS s(i)
test-> ON (s.i <= array_upper(val, 1));
id | val
+-
1 | 1
1 | 2
1 | 3
2 | 4
2 | 5
2 | 6
3 | 7
3 | 8
3 | 9
4 | 10
4 | 11
4 | 12
4 | 13
(13 rows)
--
-- Second Way (by using contrib/intagg)
--
SELECT id, int_array_enum(val) FROM t_arr;
Regards.
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