SDS Programming for business

In SQL, which clause filters groups after aggregation?

• 1 WHERE
• 2 HAVING
• 3 FROM
• 4 ORDER BY

Which SQL join keeps all rows from the left table and the matching rows from the right?

• 1 INNER JOIN
• 2 UNION
• 3 LEFT JOIN
• 4 CROSS JOIN only

In Python, which library is most commonly used for working with tables of data?

• 1 random
• 2 os
• 3 pandas
• 4 turtle

The SQL statement SELECT region, SUM(sales) FROM orders GROUP BY region returns:

• 1 One row per region with total sales
• 2 Only the largest region
• 3 The average sales
• 4 One row for each order

A join between a customer table and an orders table on the wrong column typically results in:

• 1 Fewer errors
• 2 Duplicated or incorrect rows
• 3 A faster query
• 4 No change

In Python, a list of values such as [10, 20, 30] can be used in a loop to:

• 1 Encrypt the data
• 2 Process each value in turn
• 3 Format the screen
• 4 Delete the database

A good practice when cleaning data in code is to:

• 1 Keep the raw data unchanged and make the steps repeatable
• 2 Delete all rows with any missing value
• 3 Do the work by hand without notes
• 4 Overwrite the original file