Given this dbt model config and SQL, what will be the result when run?

medium📝 Predict Output Q13 of 15

dbt - Performance Optimization

{% if is_incremental() %}
  select * from source_table where updated_at > (select max(updated_at) from {{ this }})
{% else %}
  select * from source_table
{% endif %}

Model config:

materialized: 'incremental'

AThe model will fully refresh the table every run.

BThe model will fail due to syntax error.

CThe model will create a view instead of a table.

DThe model will add only new rows with updated timestamps.

Step-by-Step Solution

Solution:

Step 1: Understand the incremental logic in SQL
The SQL uses is_incremental() to run different queries: full select on first run, then only new rows after.
Step 2: Match with incremental materialization behavior
With materialized: 'incremental', dbt appends new rows where updated_at is greater than the max in the existing table.
Final Answer:
The model will add only new rows with updated timestamps. -> Option D
Quick Check:
Incremental model adds new rows only [OK]

Quick Trick: Incremental models append new data, not full refresh [OK]

Common Mistakes:

MISTAKES

Thinking incremental always refreshes full table
Confusing view creation with incremental
Ignoring the is_incremental() condition

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Given this dbt model config and SQL, what will be the result when run?

Step 1: Understand the incremental logic in SQL

Step 2: Match with incremental materialization behavior

Final Answer:

Quick Check:

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