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* SQL query: List all the databases in the server
@ 2001-07-03 11:15 Roman Smirnov <smirnov@dresearch.de>
2001-07-03 11:44 ` Re: SQL query: List all the databases in the server Vince Vielhaber <vev@michvhf.com>
0 siblings, 1 reply; 5+ messages in thread
From: Roman Smirnov @ 2001-07-03 11:15 UTC (permalink / raw)
To: pgsql-docs
Hi all!
I need SQL analog of \l command from psql.
Something like "list databases".
Does anyone can help me?
Beforehand thank,
Roman.
^ permalink raw reply [nested|flat] 5+ messages in thread
* Re: SQL query: List all the databases in the server
2001-07-03 11:15 SQL query: List all the databases in the server Roman Smirnov <smirnov@dresearch.de>
@ 2001-07-03 11:44 ` Vince Vielhaber <vev@michvhf.com>
2001-07-03 12:35 ` Re: SQL query: List all the databases in the server Tom Ivar Helbekkmo <tih@kpnQwest.no>
0 siblings, 1 reply; 5+ messages in thread
From: Vince Vielhaber @ 2001-07-03 11:44 UTC (permalink / raw)
To: Roman Smirnov <smirnov@dresearch.de>; +Cc: pgsql-docs
On Tue, 3 Jul 2001, Roman Smirnov wrote:
> Hi all!
>
> I need SQL analog of \l command from psql.
> Something like "list databases".
If you just want a list of them you can get it from pg_database:
select datname from pg_database;
if you also want the username of the database owner you'll have to
cross pg_database.datdba to pg_user.usesysid something like this:
select d.datname,u.usename from pg_database d, pg_user u where d.datdba = u.usesysid;
Vince.
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^ permalink raw reply [nested|flat] 5+ messages in thread
* Re: SQL query: List all the databases in the server
2001-07-03 11:15 SQL query: List all the databases in the server Roman Smirnov <smirnov@dresearch.de>
2001-07-03 11:44 ` Re: SQL query: List all the databases in the server Vince Vielhaber <vev@michvhf.com>
@ 2001-07-03 12:35 ` Tom Ivar Helbekkmo <tih@kpnQwest.no>
2001-07-03 14:45 ` Re: SQL query: List all the databases in the server Tom Lane <tgl@sss.pgh.pa.us>
0 siblings, 1 reply; 5+ messages in thread
From: Tom Ivar Helbekkmo @ 2001-07-03 12:35 UTC (permalink / raw)
To: Vince Vielhaber <vev@michvhf.com>; +Cc: Roman Smirnov <smirnov@dresearch.de>; pgsql-docs
Vince Vielhaber <vev@michvhf.com> writes:
>> I need SQL analog of \l command from psql.
>> Something like "list databases".
>
> If you just want a list of them you can get it from pg_database:
>
> select datname from pg_database;
>
> if you also want the username of the database owner [...]
The psql program implements the various \-ed information commands
using SQL, and you can find the actual code by perusing its source
file "describe.c". In this case, we find that "\l" is:
SELECT pg_database.datname as "Database",
pg_user.usename as "Owner",
pg_encoding_to_char(pg_database.encoding) as "Encoding",
obj_description(pg_database.oid) as "Description"
FROM pg_database, pg_user
WHERE pg_database.datdba = pg_user.usesysid
UNION
SELECT pg_database.datname as "Database",
NULL as "Owner",
pg_encoding_to_char(pg_database.encoding) as "Encoding",
obj_description(pg_database.oid) as "Description"
FROM pg_database
WHERE pg_database.datdba NOT IN (SELECT usesysid FROM pg_user)
ORDER BY "Database";
However, the "Encoding" bits are only included if the system is
compiled with support for multiple character set encodings, and the
"Description" bits only if the command is given as "\l+", which is a
new one for me -- it's not included in "\?" output. It seems, from a
little experimentation, that that "+" suffix is available also for the
other "\" commands where it's relevant. Cool! :-)
The above SELECT is extensively reformatted from the strings it's
built from in the source file, of course.
-tih
--
The basic difference is this: hackers build things, crackers break them.
^ permalink raw reply [nested|flat] 5+ messages in thread
* Re: SQL query: List all the databases in the server
2001-07-03 11:15 SQL query: List all the databases in the server Roman Smirnov <smirnov@dresearch.de>
2001-07-03 11:44 ` Re: SQL query: List all the databases in the server Vince Vielhaber <vev@michvhf.com>
2001-07-03 12:35 ` Re: SQL query: List all the databases in the server Tom Ivar Helbekkmo <tih@kpnQwest.no>
@ 2001-07-03 14:45 ` Tom Lane <tgl@sss.pgh.pa.us>
2001-07-03 15:33 ` Re: SQL query: List all the databases in the server Roman Smirnov <smirnov@dresearch.de>
0 siblings, 1 reply; 5+ messages in thread
From: Tom Lane @ 2001-07-03 14:45 UTC (permalink / raw)
To: Tom Ivar Helbekkmo <tih@kpnQwest.no>; +Cc: Vince Vielhaber <vev@michvhf.com>; Roman Smirnov <smirnov@dresearch.de>; pgsql-docs
Tom Ivar Helbekkmo <tih@kpnQwest.no> writes:
> The above SELECT is extensively reformatted from the strings it's
> built from in the source file, of course.
An even easier way to see what queries psql emits for its backslash
commands is to start psql with -E option, then do the backslash
commands. This gives me, for example,
regression=# \l
********* QUERY **********
SELECT pg_database.datname as "Database",
pg_user.usename as "Owner"FROM pg_database, pg_user
WHERE pg_database.datdba = pg_user.usesysid
UNION
SELECT pg_database.datname as "Database",
NULL as "Owner"FROM pg_database
WHERE pg_database.datdba NOT IN (SELECT usesysid FROM pg_user)
ORDER BY "Database"
**************************
List of databases
Database | Owner
------------+----------
regression | postgres
template0 | postgres
template1 | postgres
(3 rows)
regression=#
regards, tom lane
^ permalink raw reply [nested|flat] 5+ messages in thread
* Re: SQL query: List all the databases in the server
2001-07-03 11:15 SQL query: List all the databases in the server Roman Smirnov <smirnov@dresearch.de>
2001-07-03 11:44 ` Re: SQL query: List all the databases in the server Vince Vielhaber <vev@michvhf.com>
2001-07-03 12:35 ` Re: SQL query: List all the databases in the server Tom Ivar Helbekkmo <tih@kpnQwest.no>
2001-07-03 14:45 ` Re: SQL query: List all the databases in the server Tom Lane <tgl@sss.pgh.pa.us>
@ 2001-07-03 15:33 ` Roman Smirnov <smirnov@dresearch.de>
0 siblings, 0 replies; 5+ messages in thread
From: Roman Smirnov @ 2001-07-03 15:33 UTC (permalink / raw)
To: Tom Lane <tgl@sss.pgh.pa.us>; +Cc: Tom Ivar Helbekkmo <tih@kpnQwest.no>; Vince Vielhaber <vev@michvhf.com>; pgsql-docs
Thanks to all!
Your help was very usefull
Thanks again,
Roman
^ permalink raw reply [nested|flat] 5+ messages in thread
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-- links below jump to the message on this page --
2001-07-03 11:15 SQL query: List all the databases in the server Roman Smirnov <smirnov@dresearch.de>
2001-07-03 11:44 ` Vince Vielhaber <vev@michvhf.com>
2001-07-03 12:35 ` Tom Ivar Helbekkmo <tih@kpnQwest.no>
2001-07-03 14:45 ` Tom Lane <tgl@sss.pgh.pa.us>
2001-07-03 15:33 ` Roman Smirnov <smirnov@dresearch.de>
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