Below are five ways to check if a table exists in a PostgreSQL database.

The pg_tables View

The pg_tables view contains information about each table in the database.

We can use it to check if a given table exists in the current database:

SELECT EXISTS (
    SELECT FROM 
        pg_tables
    WHERE 
        schemaname = 'public' AND 
        tablename  = 'actor'
    );

Result:

True

In this case I get True, which means that the table does exist (and I have access to it).

Depending on your configuration, you may get t/f instead of True/False.

The information_schema.tables View

The information_schema.tables view contains all tables and views defined in the current database that the current user has access to.

We can use it to check if a given table exists and that we have access to it:

SELECT EXISTS (
    SELECT FROM 
        information_schema.tables 
    WHERE 
        table_schema LIKE 'public' AND 
        table_type LIKE 'BASE TABLE' AND
        table_name = 'actor'
    );

Result:

True

Another way to do it would be to get the count:

SELECT 
    COUNT(table_name)
FROM 
    information_schema.tables 
WHERE 
    table_schema LIKE 'public' AND 
    table_type LIKE 'BASE TABLE' AND
	table_name = 'actor';

Result:

1

The table_type can be one of the following:

BASE TABLE	Persistent base table (normal table)
VIEW	View
FOREIGN	Foreign table
LOCAL TEMPORARY	Temporary table

You can omit table_type from your filter if you want to check whether the name exists across all types.

System Catalogs

The system catalogs are the place where an RDBMS stores schema metadata, such as information about tables and columns, and internal bookkeeping information.

In Postgres, system catalogs are regular tables.

We can use two of them to check if a given table exists:

SELECT EXISTS (
    SELECT FROM 
        pg_catalog.pg_class c
    JOIN 
        pg_catalog.pg_namespace n ON 
        n.oid = c.relnamespace
    WHERE  
        n.nspname = 'public' AND 
        c.relname = 'actor' AND 
        c.relkind = 'r'
    );

Result:

True

The relkind of r is for ordinary table.

You can remove the relkind filter altogether if you simply want to check whether or not an object already has the name that you want to give to a table.

Or you could filter by other types.

Here are the options:

r	ordinary table
i	index
S	sequence
t	TOAST table
v	view
m	materialized view
c	composite type
f	foreign table
p	partitioned table
I	partitioned index

The to_regclass() Function

The to_regclass() function translates a textual relation name to its OID. If the name exists, the OID is returned.

Example:

SELECT to_regclass('public.actor');

Result:

actor

If the table doesn’t exist, NULL is returned.

Cast to regclass

It’s also possible to cast the table name to type regclass:

SELECT 'public.actor'::regclass

Result:

actor

However, if the table doesn’t exist, an error occurs.

Check if a Table Already Exists Before Creating It

If you need to create the table if it doesn’t exist, you can use the IF NOT EXISTS clause of the CREATE TABLE statement. If the table doesn’t exist, it will be created. If it already exists, it won’t be created.

See Create a Table Only if it Doesn’t Exist in PostgreSQL for an example.