# SQL LOG Function

The SQL LOG function calculates the natural logarithmic value of given float value. The syntax of the SQL Server LOG Function is

```SELECT LOG (Float_Expression, base)
FROM [Source]```

Base: This is an optional argument. If you omit this argument, the SQL logarithm function will consider the default e as logarithm base. However, you can change the base value as per your requirement. The value of e is approximately equal to 2.71828

## SQL LOG Function Example 1

The SQL Logarithmic Function is used to calculate the logarithmic value of a given number with the specified base value. In this example, We use LOG function on different data and display the output

```DECLARE @i float
SET @i = 10

SELECT LOG(@i)AS [LOG Result 1]

-- Calculating LOG directly
SELECT LOG(1) AS [LOG Result 2]

SELECT LOG(96) AS [LOG Result 3]

SELECT LOG(10.90 + 15.10 - 22.50 + 1.50) AS [LOG Result 4]

-- Calculating LOG with two arguments
SELECT LOG(10, 4) AS [LOG Result 5]

SELECT LOG((10.90 + 15.10 - 22.50 + 1.50), 8) AS [LOG Result 6]```

Within this log function example query, we are calculating the logarithmic value of @i base e (It means LOG(10, e)).

`SELECT LOG(@i)AS [LOG Result 1]`

In the below SQL Server statement, We used this logarithm function directly on the float values

```SELECT LOG(1) AS [LOG Result 2]
SELECT LOG(96) AS [LOG Result 3]
SELECT LOG(10.90 + 15.10 - 22.50 + 1.50) AS [LOG Result 4]```

In the next statement, We used the SQL Server LOG Function with two arguments (float and base value). It means the logarithmic value of 10 bases 4.

`SELECT LOG(10, 4) AS [LOG Result 5]`

## SQL Logarithmic Function Example 2

In this Mathematical function example, We are going to calculate the logarithmic value of all the records present in the [StandardCost] and [Tax Amount] using LOG Function.

```SELECT [EnglishProductName]
,[Color]
,[StandardCost]
,LOG([StandardCost], 8) AS [Cost_Log result]
,[ListPrice]
,[DealerPrice]
,[SalesAmount]
,[TaxAmt]
,LOG([TaxAmt]) AS [Tax_Log result]
FROM [SQL Tutorial].[dbo].[Prod Sales]```
Categories SQL