Incremental model merge only if changes occured in certain columns

Help
1

hello!
I’m using

{{
  config(
    materialized='incremental',
    unique_key='id',
    merge_update_columns = ['phone', 'created_at']
  )
}}

but I want to update record only if changes occured in “phone” column.

for now I do it like this but it feels a bit wierd:

{{
  config(
    materialized='incremental',
    unique_key='id',
    merge_update_columns = ['phone', 'created_at']
  )
}}

WITH source_data AS (
  SELECT
    id,
    first_name AS name,
    phone,
    created_at
  FROM costumers_dbt_examples
)

SELECT
  id,
  name,
  phone,
  created_at
FROM source_data
{% if is_incremental() %}
WHERE id IN (
  SELECT id
  FROM {{ this }}
  WHERE source_data.phone != {{ this }}.phone
)
OR id NOT IN (
  SELECT id FROM {{ this }}
)
{% endif %}

Is there a built in feature in dbt that will allow me to choose which columns in source table to look for changes in?

thanks alot!

2

I may be wrong here, but rather than incremental model, this looks more like a job for snapshots with check strategy.