Data Engineering Associate with Databricks Practice Exam

Which SQL command supports multiple conditionals for updates and inserts?

1. INSERT INTO

2. COPY INTO

3. MERGE INTO

4. UPDATE TABLE

The correct answer is: MERGE INTO

The SQL command that supports multiple conditionals for updates and inserts is MERGE INTO. This command is particularly useful when you need to conditionally update records in a target table based on whether corresponding records exist in a source table. It allows for complex logic to be applied, enabling one command to handle both insertion of new records and updating of existing records in a single atomic operation. The versatility of MERGE INTO comes from its ability to specify different actions (such as insert or update) based on the existence of records that meet specific criteria. This is particularly valuable in data engineering when dealing with large datasets and the need for efficient data processing. Other SQL commands like INSERT INTO focus primarily on adding new records and do not inherently support conditional logic for updates. COPY INTO is used primarily for bulk data loading from files into a table and doesn't inherently allow for conditionals within the command. UPDATE TABLE applies to modifying existing records but does not handle insertions and requires a pre-existing record to operate on, thereby lacking the complexity needed for handling multi-condition scenarios in one command.