Multiple choice technology databases

what is the output of the the query: select 'Sql' from dual where null = null;

  1. No rows will be displayed

  2. Sql

  3. It throws Error

  4. None

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A Correct answer
Explanation

In SQL, NULL = NULL evaluates to UNKNOWN (not TRUE or FALSE). The WHERE clause only returns rows where the condition evaluates to TRUE. Since NULL comparisons with = always return UNKNOWN, no rows satisfy the condition and the query returns no output.