Is there any way to create a backup of particular row within a table in postgresql?
COPY (SELECT * FROM mytable WHERE id = 42)
TO STDOUT (FORMAT 'csv');
You can also just backup data to another table with:
create table backup as select * from mytable where id=24;
Related
Select * into exp.dbo.client from db.dbo.client
I'm trying to copy a table from one database to another in postgres and it's showing me that the references between the databases aren't implemented.
And if there an easier way to copy the whole database instead of table by table, please tell me.
After executing "create extension dblink" in the database you can after excute this query to copy tableOne from database to tableTwo, without creating it before
create table tableTwo
as
select *
from dblink('host=localhost
user=username
password=password
dbname=current_database',
'select * from tableOne') as linkable( var1 type1, var2 type2,var3 type3,... )
To clone the whole database on the same server:
CREATE DATABASE "db_new" WITH TEMPLATE "db_old" OWNER owner1
In Postgres, you can select into a temporary table, is it possible to select into temporary table using a function, sucha as
Select * into temporary table myTempTable from someFucntionThatReturnsATable(1);
Thanks!
I have many tables in different databases and want to bring them to a database.
It seems like I have to create foreign table in the database (where I want to merge them all) with schemas of all the tables.
I am sure, there is a way to automate this (by the way, I am going to use psql command) but I do not know where to start.
what I have found so far is I can use
select * from information_schema.columns
where table_schema = 'public' and table_name = 'mytable'
I added more detail explanation.
I wanted to copy tables from another database
the tables have same column names and data type
using postgres_fdw, I needed to set up a field name and data type for each tables (the table names are also same)
then, I want to union the tables have same name all to have one single table.
for that, I am going to add prefix on table
for instance, mytable in db1, mytable in db2, mytable in db3 as in
db1_mytable, db2_mytable, db3_mytable in my local database.
Thanks to Albe's comment, I managed it and now I need to figure out doing 4th step using psql command.
apart from checking if table already exists, how can we verify if it is current user-defined table in postgres
CREATE TABLE IF NOT EXISTS tbl1()
how can we verify it was created by current user if already exists?
Try Like This
SELECT count(*) as cnt FROM pg_tables t where tableowner=current_user
and tablename='Tablename' and schemaname='schemaneme'
if cnt = 0 then (CREATE Table TableName)
I want to dump a subset of a table of my postgres database. Is there a way to dump a SELECT statement without creating a view?
I need to copy a part of the table to an other postgres database.
Use COPY to dump it directly to disk.
Example (from the fine manual) using a SELECT:
COPY
(SELECT * FROM country WHERE country_name LIKE 'A%')
TO '/usr1/proj/bray/sql/a_list_countries.copy';