Does anyone know of a way to calculate the natural log of

a field in SQL server 2000 (TSQL)

thanks

Brian

LOG(FieldName)

Mikhail Berlyant

Data Integrator, Yahoo!Music www.yahoo.com

Brainbench MVP for Visual Basic www.brainbench.com

Quote:> Does anyone know of a way to calculate the natural log of

> a field in SQL server 2000 (TSQL)

> thanks

> Brian

LOG()returns the natural logarithm for the given FLOAT expression. The

bad news that what SQL calls natural logarithms are calculated by using

the base-2 system. However, the LOG10() function returns the base-10

logarithm.

Look at http://www.sosmath.com/algebra/logs/ for some help:

LN(x) =

log10(x)/log10(2.71828182845904523536028747135266249775724709369995...)

--CELKO--

===========================

Please post DDL, so that people do not have to guess what the keys,

constraints, Declarative Referential Integrity, datatypes, etc. in your

schema are.

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Brian,

Mikhail was correct. LOG() is the natural log. You can check that

select log(2.718281828459045) returns 1.0.

Joe's expression is also correct in T-SQL, though not in SQL-92. There

is no LOG() function in SQL-92.

Steve Kass

Drew University

> LOG()returns the natural logarithm for the given FLOAT expression. The

> bad news that what SQL calls natural logarithms are calculated by using

> the base-2 system. However, the LOG10() function returns the base-10

> logarithm.

> Look at http://www.sosmath.com/algebra/logs/ for some help:

> LN(x) =

> log10(x)/log10(2.71828182845904523536028747135266249775724709369995...)

> --CELKO--

> ===========================

> Please post DDL, so that people do not have to guess what the keys,

> constraints, Declarative Referential Integrity, datatypes, etc. in your

> schema are.

> *** Sent via Developersdex http://www.developersdex.com ***

> Don't just participate in USENET...get rewarded for it!

1. help: LN function use in pl/sql

Hi there:

I came cross a problem using LN (or LOG) SQL function in pl/sql code

within form 4.5 application. I am trying to do some intermediate

calculation based on one table column and store in another table column.

Her is the code from a procedure looks like:

begin

....

UPDATE one_table

SET one_col = LN(another_col) * some_constant;

.....

end;

The problem is that I can not simply compile this code, because LN is not

recognized. The reference book says that all these SQL function are

supported in PL/SQL. And I did try other SQL function like SQRT, it works

fine.

Could anyone out there help me identify the problem with that.

I'm running form 4.5 on Window 3.1 machine off ORACLE 7.3 server.

I'd appreciate very much for any help.

===========================================================================

Weixing Chen

===========================================================================

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