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EXP (Transact-SQL)

SQL Server 2005

Returns the exponential value of the specified float expression.

```
EXP ( float_expression )
```
float_expression

Is an expression of type float or of a type that can be implicitly converted to float.

float

The constant e (2.718281…), is the base of natural logarithms.

The exponent of a number is the constant e raised to the power of the number. For example EXP(1.0) = e^1.0 = 2.71828182845905 and EXP(10) = e^10 = 22026.4657948067.

The exponential of the natural logarithm of a number is the number itself: EXP (LOG (n)) = n. And the natural logarithm of the exponential of a number is the number itself: LOG (EXP (n)) = n.

A. Finding the exponent of a number

The following example declares a variable and returns the exponential value of the specified variable (`10`) with a text description.

```DECLARE @var float
SET @var = 10
SELECT 'The EXP of the variable is: ' + CONVERT(varchar,EXP(@var))
GO
```

Here is the result set.

```----------------------------------------------------------
The EXP of the variable is: 22026.5
(1 row(s) affected)
```

B. Finding exponentials and natural logarithms

The following example returns the exponential value of the natural logarithm of `20` and the natural logarithm of the exponential of `20`. Because these functions are inverse functions of one another, the return value in both cases is `20`.

```SELECT EXP( LOG(20)), LOG( EXP(20))
GO
```

Here is the result set.

```---------------------- ----------------------
20                     20

(1 row(s) affected)
```