Multiple choice technology databases

Declare a number := 5; b number := null; c number := 10; Begin if a > b AND a < c then a := c * a; end if; End; What will be the value of 'a' after execution?

  1. 50

  2. NULL

  3. 5

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The condition a > b (5 > NULL) evaluates to NULL/UNKNOWN because any comparison with NULL returns NULL. In SQL/PLSQL, NULL AND FALSE/TRUE = NULL (falsy). Since the AND condition short-circuits on the NULL result from a > b, the entire condition is false, the IF block doesn't execute, and 'a' remains unchanged at 5.

AI explanation

To answer this question, let's go through each option to understand why it is correct or incorrect:

Option A) 50 - This option is incorrect because the value of 'a' will not be multiplied by 'c' since the condition in the if statement is not satisfied.

Option B) NULL - This option is incorrect because the value of 'a' is initially 5 and it will not be set to NULL in the given code.

Option C) 5 - This option is correct because the condition in the if statement is satisfied (a > b and a < c), so the value of 'a' will be updated to the product of 'c' and 'a', which is 10 * 5 = 50. Therefore, the value of 'a' will be 5 after execution.

Option D) None of the above - This option is incorrect because the correct answer is option C, as explained above.

The correct answer is C. The value of 'a' will be 5 after execution.

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