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Tracks/NULLs and CASE

NULLs and CASE

Missing values, COALESCE, and conditional labels.

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IS NULL
COALESCE
NULLIF
CASE

0/43 solved

  1. 1—009. Employees Without a Manager
    easy
  2. 2—016. Employees With No Department
    easy
  3. 3—017. Salary Tier Label
    easy
  4. 4—021. Coalesce Missing Department Name
    easy
  5. 5—116. Return First Available Phone Number
    easy
  6. 6—117. Avoid Division by Zero with NULLIF
    easy
  7. 7—118. Find Top-Level Employees with No Manager
    easy
  8. 8—146. Find Customers Who Have Never Ordered
    easy
  9. 9—306. Find Customers with No Phone Number
    easy
  10. 10—320. Count NULL Values in a Column
    easy
  11. 11—321. Assign Letter Grades with CASE WHEN
    easy
  12. 12—327. Pick the First Non-NULL Name with COALESCE
    easy
  13. 13—037. Products Never Ordered
    medium
  14. 14—050. Order Count by Status (Conditional Aggregation)
    medium
  15. 15—063. Count Employees with Missing Salary
    medium
  16. 16—064. Revenue per Unit Sold (Safe Division with NULLIF)
    medium
  17. 17—068. Revenue by Category and Order Status
    medium
  18. 18—070. Products with Zero Total Sales
    medium
  19. 19—081. Account Running Balance
    medium
  20. 20—084. Custom Sort Priority with CASE in ORDER BY
    medium
  21. 21—190. Fill Date Gaps Using GENERATE_SERIES
    medium
  22. 22—202. Find Customers Who Have Never Placed an Order
    medium
  23. 23—229. Conditional COUNT with CASE Expression
    medium
  24. 24—231. Compare Each Employee to Their Department Average Salary
    medium
  25. 25—232. Detect Price Changes Using LAG
    medium
  26. 26—234. Classify Employees into Salary Bands Using CASE
    medium
  27. 27—240. Aggregate Orders by Weekday vs Weekend
    medium
  28. 28—248. New vs Returning Customers per Month
    medium
  29. 29—249. Repeat Purchase Rate Calculation
    medium
  30. 30—253. Sales Velocity — Units Sold per Day per Product
    medium
  31. 31—254. Inventory Days Remaining Calculation
    medium
  32. 32—258. Budget vs Actual Spend Comparison
    medium
  33. 33—262. Comparing Two Datasets with FULL OUTER JOIN
    medium
  34. 34—263. Detecting Anomalies Using Z-Score Approach
    medium
  35. 35—266. Assign Sales to Fiscal Year Quarters
    medium
  36. 36—268. Calculate Age in Years from Birthdate
    medium
  37. 37—278. Transactions More Than 3 Standard Deviations Above Mean
    medium
  38. 38—337. Order Items With No Discount Applied
    medium
  39. 39—345. Detect Overdue Invoices and Days Late
    medium
  40. 40—093. Median Salary Without PERCENTILE
    hard
  41. 41—099. Running Balance with Overdraft Detection
    hard
  42. 42—288. Time-Series Gap Filling with Zero Revenue Days
    hard
  43. 43—289. Monthly Sales Pivot Table (Jan–Dec)
    hard