[Solved] Consider the function:CREATE FUNCTION multiply_all(VARIADIC nums int[]) RETURNS int AS $ SELECT COALESCE(product, 1) FROM ( SELECT exp(sum(ln(n::float))) AS product FROM unnest(nums) AS n ) sub;... | PostgreSQL

PostgreSQL - Advanced PL/pgSQL

Consider the function:

CREATE FUNCTION multiply_all(VARIADIC nums int[]) RETURNS int AS $$
  SELECT COALESCE(product, 1) FROM (
    SELECT exp(sum(ln(n::float))) AS product FROM unnest(nums) AS n
  ) sub;
$$ LANGUAGE sql;

What will SELECT multiply_all(2, 3, 4); return?

A0

B9

C24

DError: invalid input

Step-by-Step Solution

Solution:

Step 1: Understand function logic
The function multiplies all integers by using logarithms and exponentials to avoid overflow.
Step 2: Calculate product
Input is (2, 3, 4), product is 2 * 3 * 4 = 24.
Step 3: COALESCE handles empty input
If no numbers, returns 1; here input is non-empty.
Final Answer:
24 -> Option C
Quick Check:
Multiplying 2,3,4 equals 24 [OK]

Quick Trick: VARIADIC packs ints into array for multiplication [OK]

Common Mistakes:

Confusing sum with product
Expecting error on multiple arguments
Ignoring COALESCE default

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Consider the function:

Step 1: Understand function logic

Step 2: Calculate product

Step 3: COALESCE handles empty input

Final Answer:

Quick Check:

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