---
title: "Integrating ClickHouse with PostgreSQL"
description: "Perfom SELECT and INSERT operations on data stored on a remote PostgreSQL server directly from ClickHouse"
category: "DATA_INGESTION"
support: "CORE"
docs: "https://clickhouse.com/docs/integrations/connectors/data-sources/postgres"
---

# PostgreSQL

> **Note:** It's possible that you need to authorize ClickHouse Cloud to access to your PostgreSQL instance. The full list of ClickHouse Cloud egress IP addresses is available <a href="https://clickhouse.com/docs/en/manage/security/ip-egress-traffic-list" target="_blank">here</a>.

### Use the the PostgreSQL table function
You can use the PostgreSQL table function to query remote PostgreSQL tables.

```sql
SELECT * FROM PostgreSQL('<postgres_host>:<port>', '<schema>', '<database>', '<user>', '<password>');
```

### Create a PostgreSQL table without providing a schema

You can also create a table using PostgreSQL table engine in your ClickHouse Cloud service without specifying a schema using the `CREATE TABLE AS` syntax. When ClickHouse creates the table locally, types in PostgreSQL will be mapped to equivalent ClickHouse types.

``` sql
CREATE TABLE mycountries AS PostgreSQL('<postgres_host>:5432', '', 'countries', 'postgres', '<password>');
``` 

> **Note:** You can use the setting `external_table_functions_use_nulls = 0` to ensure Null values are represented as their default values (instead of Null). If set to 1 (the default), ClickHouse will create Nullable variants of each column.


### Create a PostgreSQL table with a custom schema

You can also decide to create a table with the PostgreSQL table engine in your ClickHouse service by specifying a custom schema. 

``` sql
CREATE TABLE default.postgresql_table
(
    `float_nullable` Nullable(Float32),
    `str` String,
    `int_id` Int32
)
ENGINE = PostgreSQL('<postgres_host>:<port>', '<schema>', '<database>', '<user>', '<password>');
```