CASE, COALESCE & Functions

Preview — 3 of 10 questions

What does the following query return for a row where score = 45?

javascript

SELECT
  name,
  CASE
    WHEN score >= 90 THEN 'A'
    WHEN score >= 75 THEN 'B'
    WHEN score >= 60 THEN 'C'
    ELSE 'F'
  END AS grade
FROM students;

A'F'

B'C'

C'B'

DNULL

What does COALESCE(NULL, NULL, 'default', 'other') return?

ANULL

B'default'

C'other'

DAn error

Which of the following correctly avoids a division-by-zero error?

javascript

-- Safe division pattern
SELECT
  product,
  NULLIF(quantity_sold, 0) AS safe_divisor,
  revenue / NULLIF(quantity_sold, 0) AS avg_price
FROM sales;

ASELECT total / count FROM orders

BSELECT total / NULLIF(count, 0) FROM orders

CSELECT COALESCE(total / count, 0) FROM orders

DSELECT ISNULL(total / count, 0) FROM orders

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