Log base 10 calculation in Access

[dt2demar]

I am puzzled by this seemingly simple task to calculate the log base 10 of a field of values. Any help would be greatly appreciated.

The natural log (ln) is easy to calculate: If 'field1' contains a list of numbers, then 'field2: log([field1])'.

How can I so the same for a log base-10?
'field2: log10([field1])' does not work. Unlike excel, Access is very limited in it's functions. I think I will have to program this in VBA to get it to work. If so, how would I do that?

 

[petermeachem]

If memory serves me, log10 (x) = ln(10) * ln(x). I find the childrens homework sites really useful for this type of thing which fell out of my brain many years ago! Peter Meachem
peter@accuflight.com

 

[dt2demar]

Thanks for your response, but your relationship is incorrect. Example:

log(0.001) = -3

ln(10)=2.3
ln(0.001)=-6.9
ln(10)*ln(0.001)=-15.88

log(0.001) does not equal ln(10)*ln(0.001)

Perhaps I could manipulate the 'exponent' function in some way to calculate a log, but I doubt it.

 

[tlbroadbent]

The function is LogN(X) = Log(X) / Log(N) Or Log10(X) = Log(X) / Log(10)

You can find more derived functions in Access Help under the title "Derived Math Functions."

Terry

X-) "I don't have a solution, but I admire your problem."

 

[dt2demar]

thanks for your help!

 

[petermeachem]

Well I wasn't that far out was I tbroadbent. You recall we were talking about why my customer had this strange sql server login problem? Eventually I went up to see them, together with the hardware suppliers. It turned out they had installed sql not in the nt domain. All better now. Peter Meachem
peter@accuflight.com

 

[dt2demar]

Thank-you too Petermeachem. You were very close. I have forgotten a lot more about logarithms than I realized!!

 

[MichaelRed]

Actually try thre help system.

Log Function


Returns a Double specifying the natural logarithm of a number.

Syntax

Log(number)

The required number argument is a Double or any valid numeric expression greater than zero.

Remarks

The natural logarithm is the logarithm to the base e. The constant e is approximately 2.718282.

You can calculate base-n logarithms for any number x by dividing the natural logarithm of x by the natural logarithm of n as follows:

Logn(x) = Log(x) / Log

The following example illustrates a custom Function that calculates base-10 logarithms:

Static Function Log10(X)
Log10 = Log(X) / Log(10#)
End Function


MichaelRed
redmsp@erols.com

There is never time to do it right but there is always time to do it over