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How to calculate the infinite product by SQL

How to calculate the infinite product by SQL

Description

I needed to calculate the infinite product in the creating ETL script. So I thought the solution to calculate it in the SQL. The following way is the solution I thought.

Premise

  • Use the standard SQL

Code

WITH sample_table AS
(
    SELECT 2 AS n1, 4 AS n2
    UNION ALL
    SELECT 4, 8
    UNION ALL
    SELECT 10, 20
    UNION ALL
    SELECT 10, 20
)
SELECT * FROM sample_table
UNION ALL
SELECT
    CAST(EXP(SUM(LOG(n1))) AS INT64) AS inf_product1,
    CAST(EXP(SUM(LOG(n2))) AS INT64) AS inf_product2
FROM sample_table

The infinite product (∏) is able to convert to the total addition formula.

  • ∏n1 ≒ eΣlogen1
  • ∏n2 ≒ eΣlogen2

Finally

Actually, this calculated value is an approximation. So if you want an accurate number, this solution cannot use.

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