PostgreSQL Node: Fixed String $1 Misinterpreted as Placeholder in Execute Query Operation

[tumf]

Bug Description

When using the PostgreSQL node in n8n with the "Execute Query" operation, if the query contains the fixed string $1, it is incorrectly interpreted as a placeholder, causing an error.

Example Query:

select '$1'

Error Message:

Variable $1 out of range. Parameters array length: 0
Failed query: select '$1'

This query, when executed directly in PostgreSQL, correctly returns the string $1. However, in n8n, it is treated as a placeholder, leading to the mentioned error.

To Reproduce

1. Create a workflow in n8n.
2. Add a PostgreSQL node.
3. Set the operation to "Execute Query".
4. Use the query:

   select '$1'
   

5. Execute the workflow.

Expected behavior

The query select '$1' should return the string $1 when executed in the PostgreSQL node, similar to how it behaves when run directly in PostgreSQL.

Operating System

Ubuntu 24.04. LTS

n8n Version

1.44.1

Node.js Version

20.13.1

Database

PostgreSQL

Execution mode

queue

[Joffcom]

Thanks for the report, I have managed to reproduce this and have created NODE-1416 as the internal ticket to get this fixed. Out of interest and so we can set a priority to it... Do you use $x a lot in your queries?

[tumf]

I think this issue is critical for PostgreSQL becasue the issue prevents the execution of very common SQL such as the following example:
insert into comments (id, text) values (2, "His efforts have resulted in a $1000 salary increase.”)

Of course, this problem can be bypassed by using a PREPARED STATEMENT as follows.
insert into comments (id, text) values (2, $1)
Query parameters: "His efforts have resulted in a $1000 salary increase.”

[Joffcom]

That value makes perfect sense, This is in the queue to be picked up so should be resolved soon.