Databricks Certified Data Engineer - Associate
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Which of the following code blocks will remove the rows where the value in column age is greater than 25 from the existing Delta table my_table and save the updated table?
Real Exam
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KKeng
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A
SELECT * FROM my_table WHERE age > 25;
B
UPDATE my_table WHERE age > 25;
C
DELETE FROM my_table WHERE age > 25;
D
UPDATE my_table WHERE age <= 25;
E
DELETE FROM my_table WHERE age <= 25;
Explanation:
Explanation
The correct answer is C. DELETE FROM my_table WHERE age > 25;
Here's why:
-
DELETE statement: The DELETE statement is specifically designed to remove rows from a table based on a condition. The syntax
DELETE FROM table_name WHERE conditionremoves rows that match the condition. -
Understanding the requirement: The question asks to "remove the rows where the value in column age is greater than 25". This means we need to delete rows where
age > 25. -
Analyzing other options:
- A:
SELECT * FROM my_table WHERE age > 25;- This only selects/reads the rows but doesn't remove them. - B:
UPDATE my_table WHERE age > 25;- This is invalid syntax (UPDATE requires SET clause) and even if corrected, UPDATE modifies existing rows rather than removing them. - D:
UPDATE my_table WHERE age <= 25;- Similar to B, invalid syntax and UPDATE doesn't remove rows. - E:
DELETE FROM my_table WHERE age <= 25;- This would delete rows where age is 25 or less, which is the opposite of what's requested.
- A:
-
Delta table context: In Databricks with Delta tables, the DELETE operation is transactional and maintains ACID properties, ensuring data consistency while removing rows.
Key takeaway: Use DELETE FROM table_name WHERE condition to remove specific rows from a Delta table in Databricks.
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