A Friendly Reminder: One Plus NULL Equals NULL

When performing arithmetic operations across SQL columns, it is crucial to handle NULL values appropriately, as these can result in entire records being invalidated if not managed correctly. For example, in a sales record scenario with varying jurisdictions and product categories, NULL values in columns such as sales tax or hazardous materials fees can lead to inaccurate total cost calculations when using simple addition. The COALESCE function can be employed to substitute NULL values with a default value, such as zero, ensuring that calculations yield accurate results even in the presence of missing data. This approach is emphasized with the introduction of Fivetran Transformations, which allows for more efficient data handling within data warehouses.