In this post, I am sharing a quick way to move your table with data from one schema to another schema of PostgreSQL.

I already shared an article on, how to copy a table from one schema to another schema.

PostgreSQL: Script to copy Table Data from one Schema to another Schema

For moving the table between the schemas is a very simple, you should just update the entry in pg_class and pg_type table.
Something like update the table schema name from old to the new basis on given table name.

Please check the below solution, try it your self:

UPDATE pg_catalog.pg_class
SET relnamespace = (SELECT oid FROM pg_catalog.pg_namespace
                    WHERE nspname = 'destination_schema')
WHERE relnamespace = (SELECT oid FROM pg_catalog.pg_namespace
                      WHERE nspname = 'source_schema')
AND relname = 'table_name';

UPDATE pg_catalog.pg_type
SET typnamespace = (SELECT oid FROM pg_catalog.pg_namespace
                    WHERE nspname = 'destination_schema')
WHERE typnamespace = (SELECT oid FROM pg_catalog.pg_namespace
                      WHERE nspname = 'source_schema')
AND typname = 'table_name';

In this post, I am sharing the different options to check weather your table exists in your database or not.

For checking the existence of table is a ubiquitous requirement for PostgreSQL Database Developer.
PostgreSQL 9.4 introduced to_regclass to check object presence very efficiently.

You can check other below options as well.

Use to_regclass (From PostgreSQL 9.4): This is the fastest option.

SELECT to_regclass('schema_name.table_name');

Use information_schema.tables:

SELECT EXISTS 
(
	SELECT 1
	FROM information_schema.tables 
	WHERE table_schema = 'schema_name'
	AND table_name = 'table_name'
);

Use catalogs tables:

SELECT EXISTS 
(
	SELECT 1 
	FROM pg_catalog.pg_class c
	JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
	WHERE n.nspname = 'schema_name'
	AND c.relname = 'table_name'
	AND c.relkind = 'r' -- r = tables 
);

Use pg_tables catalog:

SELECT EXISTS 
(
	SELECT 1 
	FROM pg_tables
	WHERE schemaname = 'schema_name'
	AND tablename = 'table_name'
);

In this post, I am sharing one SQL Script to find the size of all your PostgreSQL Databases.

I am sharing this kind of script because It helps a lot for reporting and monitoring Database Server.

Recently, I have used this script to generate all database size reports because suddenly one of our PostgreSQL Server increased utilization of the Disk.

Using pg_catalog.pg_database, I am finding the size of Databases.
Below is a script:

SELECT 
	datname AS DatabaseName
	,pg_catalog.pg_get_userbyid(datdba) AS OwnerName
	,CASE 
		WHEN pg_catalog.has_database_privilege(datname, 'CONNECT')
		THEN pg_catalog.pg_size_pretty(pg_catalog.pg_database_size(datname))
		ELSE 'No Access For You'
	END AS DatabaseSize
FROM pg_catalog.pg_database
ORDER BY 
	CASE 
		WHEN pg_catalog.has_database_privilege(datname, 'CONNECT')
		THEN pg_catalog.pg_database_size(datname)
		ELSE NULL
	END DESC;