atan-transact-sql.md

title	ATAN (Transact-SQL) | Microsoft Docs
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ms.date	07/24/2017
ms.prod	sql-non-specified
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ms.technology	database-engine
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ms.topic	language-reference
f1_keywords	ATAN_TSQL ATAN
dev_langs	TSQL
helpviewer_keywords	arctangent ATAN function tangent
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ATAN (Transact-SQL)

[!INCLUDEtsql-appliesto-ss2008-all_md]

Returns the angle in radians whose tangent is a specified float expression. This is also called arctangent.

Transact-SQL Syntax Conventions

Syntax

-- Syntax for SQL Server, Azure SQL Database, Azure SQL Data Warehouse, Parallel Data Warehouse  
  
ATAN ( float_expression )  

Arguments

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

Return types

float

Examples

The following example takes a float expression and returns the ATAN of the specified angle.

SELECT 'The ATAN of -45.01 is: ' + CONVERT(varchar, ATAN(-45.01))  
SELECT 'The ATAN of -181.01 is: ' + CONVERT(varchar, ATAN(-181.01))  
SELECT 'The ATAN of 0 is: ' + CONVERT(varchar, ATAN(0))  
SELECT 'The ATAN of 0.1472738 is: ' + CONVERT(varchar, ATAN(0.1472738))  
SELECT 'The ATAN of 197.1099392 is: ' + CONVERT(varchar, ATAN(197.1099392))  
GO  

[!INCLUDEssResult]

  
-------------------------------   
The ATAN of -45.01 is: -1.54858                         
  
(1 row(s) affected)  
  
--------------------------------   
The ATAN of -181.01 is: -1.56527                         
  
(1 row(s) affected)  
  
--------------------------------   
The ATAN of 0 is: 0                                
  
(1 row(s) affected)  
  
----------------------------------   
The ATAN of 0.1472738 is: 0.146223                         
  
(1 row(s) affected)  
  
-----------------------------------   
The ATAN of 197.1099392 is: 1.56572                          
  
(1 row(s) affected)  

Examples: [!INCLUDEssSDWfull] and [!INCLUDEssPDW]

The following example takes a float expression and returns the arctangent of the specified angle.

SELECT ATAN(45.87) AS atanCalc1,  
    ATAN(-181.01) AS atanCalc2,  
    ATAN(0) AS atanCalc3,  
    ATAN(0.1472738) AS atanCalc4,  
    ATAN(197.1099392) AS atanCalc5;  

[!INCLUDEssResult]

atanCalc1 atanCalc2 atanCalc3 atanCalc4 atanCalc5

--------- --------- --------- --------- ---------

1.55 -1.57 0.00 0.15 1.57

See also

CEILING (Transact-SQL)
Mathematical Functions (Transact-SQL)