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Handling NULL Values
NULL means 'unknown', not zero. Find passengers whose age is NULL (unknown). Show name, pclass, fare, and a column called age_display that shows 'Unknown' when age is NULL, or the age value when it's known. Sort by fare descending. Limit to 15 rows.
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Schema
passengers
| passenger_id | survived | pclass | name | sex | age | sibsp | parch | fare | embarked |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 0 | 3 | Braund, Mr. Owen Harris | male | 22 | 1 | 0 | 7.25 | S |
| 2 | 1 | 1 | Cumings, Mrs. John Bradley | female | 38 | 1 | 0 | 71.28 | C |
| 3 | 1 | 3 | Heikkinen, Miss. Laina | female | 26 | 0 | 0 | 7.93 | S |
Expected output: age_display shows 'Unknown'
Hint
Concepts
SELECT IS NULL COALESCE NULL Handling
Practise the topic: SQL practice questions · NULL handling practice
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