Thread: very simple: How can I multiply tables?
Hi, question How can I multiply tables using SELECT? Table 1 id surname -------------- 1 AAA 2 BBB 3 CCC 4 DDD Table 2 dt --- 12 35 RESULT id surname dt --------------------------- 1 AAA 12 2 BBB 12 3 CCC 12 4 DDD 12 1 AAA 35 2 BBB 35 3 CCC 35 4 DDD 35
On Wed, Feb 14, 2001 at 05:49:01PM +0300, Mikhail V. Majorov wrote: > Hi, question > > How can I multiply tables using SELECT? > > Table 1 > > id surname > -------------- > 1 AAA > > Table 2 > > dt > --- > 12 > > RESULT > > id surname dt > --------------------------- > 1 AAA 12 I think what you want is the following: table1: id surename =========== 1 AAA table2: id dt ===== 1 12 select table1.id as id, table1.surname as surname, table2.dt as dt from table1, table2 where table1.id = table2.id; -- SC-Networks www: www.SC-Networks.de Web Design, Netzwerke, 3D Animation und Multimedia Heiko Irrgang Tel.: 08856/9392-00 Im Thal 2 Fax: 08856/9392-01 82377 Penzberg Mail: Irrgang@SC-Networks.de
INSERT INTO table3 (id, surname, dt) SELECT table1.id, table1.surname, table2.dt FROM table1, table2;
or
CREATE TABLE table3 AS SELECT table1.id, table1.surname, table2.dt FROM table1, table2;
It's called a cross-join.
Cheers...
MikeA
-----Original Message-----
From: Mikhail V. Majorov [mailto:mik@ttn.ru]
Sent: 14 February 2001 14:49
To: pgsql-general@postgresql.org
Subject: [GENERAL] very simple: How can I multiply tables?
Hi, question
How can I multiply tables using SELECT?
Table 1
id surname
--------------
1 AAA
2 BBB
3 CCC
4 DDD
Table 2
dt
---
12
35
RESULT
id surname dt
---------------------------
1 AAA 12
2 BBB 12
3 CCC 12
4 DDD 12
1 AAA 35
2 BBB 35
3 CCC 35
4 DDD 35
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Yes, very simple!
> How can I multiply tables using SELECT?
select * from tbl1, tbl2;
With kind regards / Mit freundlichem Gruß
Holger Klawitter
--
Holger Klawitter
holger@klawitter.de http://www.klawitter.de
Holger Klawitter wrote:
>
> Yes, very simple!
>
> > How can I multiply tables using SELECT?
>
> select * from tbl1, tbl2;
I think so. But in real I have some problem with empty table.
Please, look at my example.
ttn=# create table t3 (id int4, surname text);
CREATE
ttn=# create table t2 (dt int4);
CREATE
ttn=# insert into t2 values ('4');
INSERT 34461 1
ttn=# insert into t2 values ('56');
INSERT 34462 1
ttn=# select * from t2,t3;
dt | id | surname
----+----+---------
(0 rows)
ttn=#
As I know theory I must see this:
dt | id | surname
----+----+---------
4 null null
56 null null
Result is change when I insert data in t3.
ttn=# insert into t3 values ('100', 'test');
INSERT 34463 1
ttn=# insert into t3 values ('101', 'test2');
INSERT 34464 1
ttn=# select * from t2,t3;
dt | id | surname
----+-----+---------
4 | 100 | test
56 | 100 | test
4 | 101 | test2
56 | 101 | test2
(4 rows)
ttn=#
Is it bug or normal?
Best regards,
Mik.
> Michael Ansley wrote: > > INSERT INTO table3 (id, surname, dt) SELECT table1.id, table1.surname, > table2.dt FROM table1, table2; > or > CREATE TABLE table3 AS SELECT table1.id, table1.surname, table2.dt > FROM table1, table2; > > It's called a cross-join. You are absolutely right. But I don't find any information about JOIN in SELECT sentences. :( Could you give me example of LEFT or RIGHT JOIN. Best regards, Mik.