PostgreSQL Node

The PostgreSQL node allows you to execute queries and operations on a PostgreSQL database. It offers both a visual query builder and the option to write custom SQL.

Overview

Connection

Using Saved Credentials (Recommended)

Select a credential of type PostgreSQL in the Credential field. The credential contains all connection information.

Manual Configuration

Connection String:

postgresql://user:password@host:5432/database?sslmode=require

Query Modes (Presets)

Custom SQL

Write SQL freely with parameter support.

Example:

SELECT * FROM users WHERE email = $1 AND active = $2

Parameters: ["john@example.com", true]

Security: Always use parameters ($1, $2) instead of concatenating values directly in SQL. This prevents SQL injection.

SELECT (Visual Builder)

Build SELECT queries without writing SQL:

WHERE Conditions:

EXISTS

Checks whether at least one record matching the criteria exists.

Returns rowCount: 1 if it exists, rowCount: 0 if it does not exist.

COUNT

Counts records matching the criteria.

ASSERT

Checks whether a value in the database matches the expected value. Ideal for data validations.

INSERT

Inserts new records.

Example:

UPDATE

Updates existing records.

DELETE

Removes records.

Outputs

Accessing Outputs

// All records
{{ steps.query.outputs.rows }}

// First record
{{ steps.query.outputs.rows[0] }}

// Specific field from the first record
{{ steps.query.outputs.rows[0].name }}  →  "John"
{{ steps.query.outputs.rows[0].email }}  →  "john@example.com"

// Count
{{ steps.query.outputs.rowCount }}  →  5

Practical Examples

Validate data after creation via API

[HTTP Request: POST /api/users → body: { "name": "John" }]
    │
    ▼
[PostgreSQL: SELECT * FROM users WHERE name = 'John']
    │
    ▼
[If: {{ steps.query.outputs.rowCount }} > 0]
    │ true → [Log: "User successfully created in the database"]
    │ false → [Stop and Fail]

Prepare data for testing

[PostgreSQL: INSERT INTO test_data (key, value) VALUES ('token', 'abc123')]
    │
    ▼
[HTTP Request: GET /api/verify?token={{ steps.insert.outputs.rows[0].token }}]

Clean up data after testing

[... tests ...]
    │
    ▼
[PostgreSQL: DELETE FROM test_data WHERE created_by = 'automated-test']

Tips

• Use saved credentials to manage connections in a centralized way
• Use parameters ($1, $2) in custom SQL to prevent SQL injection
• The visual query builder is ideal for simple operations and is less prone to syntax errors
• Use expressions in values: {{ steps.api.outputs.json.id }} to use data from previous nodes
• Test the connection before running the flow using the test button on the credentials screen