Multiple choice technology databases

select dummy from dual minus select * from dual what would be output ?

  1. No rows returned

  2. Error: invalid SQL statement

  3. Error: invalid identifier

  4. Error: syntax error

  5. 1 row
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A Correct answer
Explanation

The DUAL table contains exactly one column named DUMMY and one row with the value 'X'. Because select dummy from dual and select * from dual both return exactly the same single row (X), subtracting one from the other via MINUS yields an empty set with no rows.

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