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Pregunta 6

In PostgreSQL 18, what does SELECT ROW(NULL::int, 1) = ROW(NULL::int, 2); return?

  1. NULL
  2. falseRespuesta correcta
  3. true
  4. It raises an error

Explicación

Row equality returns false as soon as any pair of corresponding fields is non-null and unequal, so 1 <> 2 settles the comparison and the null in the first field is never reached. NULL is only the answer when no pair is unequal and at least one pair involves a null - SELECT ROW(NULL::int, 1) = ROW(NULL::int, 1); does return NULL.

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Pregunta 6: In PostgreSQL 18, what does SELECT ROW(NULL::int, 1) =… · SQL: NULL, Joins and Aggregates · Questena