Data Engineering Associate with Databricks Practice Exam

The syntax 'USING updates u' in a SQL merge command indicates what?

1. Source of new data being merged

2. The target table being updated

3. Condition for deletion of records

4. Unique identifier for matching records

The correct answer is: Source of new data being merged

The syntax 'USING updates u' in a SQL merge command specifies the source of new data being merged into the target table. It defines a temporary table or dataset, which contains the records that will be evaluated for the merge operation. This operation typically involves comparing the records in the source (updates) with those in the target table to determine which records should be inserted, updated, or possibly deleted based on certain conditions. This distinction is important because understanding where the data originates from helps in accurately managing data changes during the merge operation. Accurately identifying the source is critical for ensuring that the right data is integrated into the target system and that intended updates are applied correctly. The other choices do not accurately capture the function of this particular syntax. The target table being updated refers to a different aspect of the merge command, while the condition for deletion or unique identifier for matching records relates to their respective roles in the merge process but are not represented by the 'USING' clause. Thus, it is the role of 'USING' as a source of new data that makes the statement valid.