LN function - AWS Clean Rooms
SyntaxArgumentReturn typeExample

LN function

The LN function returns the natural logarithm of the input parameter.

The LN function is a synonym of the DLOG1 function.

Syntax

LN(expression)

Argument

expression

The target column or expression that the function operates on.

Note

This function returns an error for some data types if the expression references an AWS Clean Rooms user-created table or an AWS Clean Rooms STL or STV system table.

Expressions with the following data types produce an error if they reference a user-created or system table.

  • BOOLEAN

  • CHAR

  • DATE

  • DECIMAL or NUMERIC

  • TIMESTAMP

  • VARCHAR

Expressions with the following data types run successfully on user-created tables and STL or STV system tables:

  • BIGINT

  • DOUBLE PRECISION

  • INTEGER

  • REAL

  • SMALLINT

Return type

The LN function returns the same type as the expression.

Example

The following example returns the natural logarithm, or base e logarithm, of the number 2.718281828: 

select ln(2.718281828);
ln
--------------------
0.9999999998311267
(1 row)

Note that the answer is nearly equal to 1.

This example returns the natural logarithm of the values in the USERID column in the USERS table: 

select username, ln(userid) from users order by userid limit 10;

 username |        ln
----------+-------------------
 JSG99FHE |                 0
 PGL08LJI | 0.693147180559945
 IFT66TXU |  1.09861228866811
 XDZ38RDD |  1.38629436111989
 AEB55QTM |   1.6094379124341
 NDQ15VBM |  1.79175946922805
 OWY35QYB |  1.94591014905531
 AZG78YIP |  2.07944154167984
 MSD36KVR |  2.19722457733622
 WKW41AIW |  2.30258509299405
(10 rows)