Multiple choice technology databases

Which Function can return a non-Null value if passed null arguments?

  1. NULLIF

  2. LENGTH

  3. CONCAT

  4. INSTR

  5. TAN
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C Correct answer
Explanation

CONCAT can return non-null when passed NULL arguments. In most SQL dialects, CONCAT with NULL arguments treats NULL as an empty string, producing a non-NULL result. For example, CONCAT(NULL, 'a') or CONCAT(NULL, NULL) typically returns a non-null string (empty or partial result). Other functions like LENGTH, NULLIF, INSTR, TAN generally return NULL when any argument is NULL.

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