Multiple choice technology databases

How many columns are presented after executing this query: SELECT address1||','||address2||','||address2 "Address" FROM employee;

  1. 1

  2. 2

  3. 3

  4. 4
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The query uses the || operator to concatenate multiple address fields and string literals into a single output string. The alias 'Address' is assigned to this single combined expression, resulting in exactly one output column. Other options incorrectly count the source columns instead of the output columns.

AI explanation

To answer this question, let's break down the query:

The query is selecting three columns: address1, address2, and address2. However, these columns are concatenated using the double pipe operator (||) and separated by commas.

So, after executing the query, the result will be a single column called "Address" that contains the concatenated values of address1, address2, and address2 (which seems to be a typo and should probably be address3).

Therefore, the correct answer is A) 1.

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