Databricks Certified Data Engineer - Associate

Explanation

To remove rows from a Delta table where a condition is met, you need to use the DELETE statement with a WHERE clause that specifies which rows to delete.

Let's analyze each option:

A. SELECT * FROM my_table WHERE age > 25;

• This is a query that only selects rows where age > 25, but it doesn't modify or delete any data from the table.

B. UPDATE my_table WHERE age > 25;

• This is syntactically incorrect. The UPDATE statement requires a SET clause to specify what columns to update. Even if it were complete, it would update rows, not delete them.

C. DELETE FROM my_table WHERE age > 25;

• ✅ CORRECT: This statement correctly deletes rows from my_table where the age column value is greater than 25. The DELETE FROM syntax removes entire rows that match the condition.

D. UPDATE my_table WHERE age <= 25;

• This would update rows where age is less than or equal to 25 (the opposite of what we want), and it's also missing the required SET clause.

E. DELETE FROM my_table WHERE age <= 25;

• This would delete rows where age is less than or equal to 25, which is the opposite of what the question asks for.

Key Points:

• In SQL, DELETE is used to remove rows from a table
• The WHERE clause specifies which rows to delete
• For Delta tables in Databricks, DELETE operations are transactional and maintain ACID properties
• The correct syntax is: DELETE FROM table_name WHERE condition;