Question

What is the result of the following arithmetic operation in SQL: SELECT 5 + NULL AS RESULT?

• A. 5
• B. NULL
• C. 0
• D. 5NULL

Answer 1

The Correct Option is B

The result of the arithmetic operation 5 + NULL in SQL is NULL.

Additional Context:

• NULL Handling in SQL:
  • Any arithmetic operation with NULL yields NULL
  • NULL represents unknown/missing data
  • Follows three-valued logic (TRUE, FALSE, UNKNOWN)
• Example Scenarios:
  • 5 + NULL → NULL
  • NULL * 10 → NULL
  • 100 / NULL → NULL
• Practical Implications:
  • Use IS NULL/IS NOT NULL for checks
  • COALESCE() or ISNULL() to handle NULLs
• Database Standards:
  • Behavior consistent across MySQL, PostgreSQL, SQL Server
  • ANSI SQL specification requirement

Correct Answer: (2) NULL.