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VivekVishwanat3's avatar
VivekVishwanat3
Qrew Cadet
6 years ago

How to multiply all the record values of a Field?

Field1     Field2
1             3
2             5
3             7
4             2



I need to do 3*5*7*2=210
And I want to show the result as


Field1     Field2       Field3 
1             3               210
2             5               210
3             7               210
4             2               210


I'm able to figure out the way to make Multiplication possible. Please Help.

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  • _anomDiebolt_'s avatar
    _anomDiebolt_
    Qrew Elite
    6 years ago
    Follow these steps:
    1. Create a field Ln([Field2]) in the child table (your existing table)
    2. Summarize this field to the parent field named [SumLog] using addition
    3. Create a formula field in the parent  table named [Product] and set it equal to the formula Exp([Product])
    4. In the child table lookup the field [Product] from the parent
    This works because Law of Logarithms:

    3 * 5 * 7 * 2 = exp( ln(3) + ln(5) + ln(7) + ln(2) )= 210

    Then go watch Standard Deviants:

    Standard Deviants: Pre-Calculus Module 6 - Logarithms
    https://www.amazon.com/Standard-Deviants-Pre-Calculus-Module-Logarithms/dp/B000A2EKTA
    • QuickBaseCoachD's avatar
      QuickBaseCoachD
      Qrew Captain
      6 years ago
      Thx Dan, I can't imagine when i would need this, but you never know.  I tried is on a calculator and it works.  I think in a previous life I used to know that.
    • _anomDiebolt_'s avatar
      _anomDiebolt_
      Qrew Elite
      6 years ago
      > I tried is on a calculator and it works.

      Of course it works - its just simple math.

      As a remedial measure I suggest you binge watch a few seasons of Numb3ers starting with this promo:



      He's a mathematician. And He's an FBI agent. And they're both brothers.
      https://www.youtube.com/watch?v=EVSFzswY3XY

      I created a demo



      Multiply Child Fields ~ View [Record ID#]= 1
      https://haversineconsulting.quickbase.com/db/bnp7nxxq7?a=dr&r=b&rid=1

      There are two formulas - one in the child table where [Ln] is calculated as:

      Ln([Number])

      and one in the parent table where [Product] is calculated as:

      Exp([SumLn])

      [SumLn] is a Summary field in Table #1 and [Product] is a lookup table in Table #2.




      Pastie Database
      https://haversineconsulting.quickbase.com/db/bgcwm2m4g?a=dr&rid=655

      Notes:

      (1) you can add your own data to test the application

      (2) you can't enter negative numbers as Ln(x) is not defined for negative numbers.
  • QuickBaseCoachD's avatar
    QuickBaseCoachD
    Qrew Captain
    6 years ago
    You will need to create a new table in the app with a single record in it. It will be Record ID 1.


    Then make a formula on your details table of 1 and make a relationship.


    Then make a sum of a field which multiplied the two numbers.


    That is called the �dot product�.

    https://en.m.wikipedia.org/wiki/Dot_p...
    • VivekVishwanat3's avatar
      VivekVishwanat3
      Qrew Cadet
      6 years ago
      Hi, I din't understand the second line. " Then make a formula on your details table of 1 and make a relationship". 
    • QuickBaseCoachD's avatar
      QuickBaseCoachD
      Qrew Captain
      6 years ago
      You need to connect every one of your records to hat single record in he new table.  The record ID of the single record will be record ID 1.
      So just make a formula field with a formula of 1 and use that as the reference field in the relationship on he right hand side.
    • VivekVishwanat3's avatar
      VivekVishwanat3
      Qrew Cadet
      6 years ago
      Yah but, How can I make a formula of Multiplication "3*5....." in the formula Field. As 3 and 5 are from different rows?
      And What exactly you are saying when you are saying "formula of 1"?