Preview works similarly to Retrieve , since both run a SOQL query to fetch source data. The difference lies in their purpose across rules engines:

• Retrieve

  • In #Batch defines and filters source data during execution, determining which records are processed.

  • In #Data List defines the query used to display records.

• Preview

  • In #Triggers input data comes from the trigger context (records being inserted, updated, or deleted).

  • In #Action Buttons : input data comes from the loaded record in the Lightning Record Page.

  • Preview does not influence which records are processed.

Both Retrieve and Preview let you view source records and inspect transformed values before execution—making it easy to validate queries, data, and transformations.