Multiple choice technology databases

select * from dual ?

  1. A

  2. X

  3. NULL

  4. Error: Invalid SQL statement

  5. Error: Invalid Identifier
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In Oracle SQL, the DUAL table is a dummy table containing a single row with a single column DUMMY that has the value 'X'. Querying it with select * retrieves this default row and returns 'X'.

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