Transform results of a PostgreSQL query for CSV output

  • I have a simple database query select * from listings where channel_code = {{select1.value}}
  • I'd like to export the results of this query as CSV format while renaming specific column headers. I want to do this so that the CSV I export matches the expected format/header column names of the downstream system that I will subsequently upload to

I saw this topic here on the Community: Export Data as CSV from JS

But I have the following questions/issues:

  1. When I try to call utils.downloadFile I receive a warning that utils is undefined.
  2. I am trying to write the transformer directly in the "Transform Results" section of the SQL query. What's the correct way to accomplish the above using this feature?

I am not a Javascript expert.


Hi @zhifengkoh, use the event handlers for download action. Transformer in this instance would require you to return the data of your query.

Hi jocen,

What if I need to change the names of the column headers?

Hi @zhifengkoh ,

As your querying a postgres db, the easiest way to make the headers match is by changing your query so the columns use aliases.

So instead of select * from table, do:

Column1 as “newcolumnname”,
Column2 as “newname”
From table

Now your result will immediately have the correct columnnames.

This is a much easier way to do that... and so DUH. Thank you!

As an additional bonus for anyone who finds this post in future, Postgres doesn't have virtual columns like MySQL but it does allow you to generate hard-coded columns on the fly, like so:

select product_name, currency, price, 'ABCXYZ' as "Vendor", '' as "Discount"
from products

Then the resulting table will have a column called "Vendor" with every cell filled with value "ABCXYZ", and a column called "Discount" with every cell filled with a blank value.

I found this useful because I'm trying to use the SQL query to generate a CSV file and the system I am uploading the CSV file to expects certain columns to exist that don't exist in my DB.

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