In Oracle, the ATAN2() function returns the arctangent (inverse tangent) of its two arguments.

Syntax

The syntax goes like this:

ATAN2(n1 , n2)

Where n1 can be in an unbounded range and returns a value in the range of –pi to pi, depending on the signs of n1 and n2, expressed in radians.

Example

Here’s an example:

SELECT ATAN2(0.3, 0.7)
FROM DUAL;

Result:

                              ATAN2(0.3,0.7) 
____________________________________________ 
   0.404891786285083423312072929009442616553

Non-Numeric Argument

The arguments can be any numeric data type or any nonnumeric data type that can be implicitly converted to a numeric data type.

Here’s what happens when we provide a non-numeric argument that can’t be converted to a numeric data type:

SELECT ATAN2('One', 0.2)
FROM DUAL;

Result:

Error starting at line : 1 in command -
SELECT ATAN2('One', 0.2)
FROM DUAL
Error report -
ORA-01722: invalid number

However, here’s what happens when we change the one to 1 and keep the quotes:

SELECT ATAN2('1', '0.2')
FROM DUAL;

Result:

                           ATAN2('1','0.2') 
___________________________________________ 
   1.37340076694501586086127192644496114865 

Null Values

If any argument is null, the result is null:

SET NULL 'null';

SELECT 
    ATAN2(null, 0.3),
    ATAN2(0.3, null),
    ATAN2(null, null)
FROM DUAL;

Result:

   ATAN2(NULL,0.3)    ATAN2(0.3,NULL)    ATAN2(NULL,NULL) 
__________________ __________________ ___________________ 
              null               null                null

By default, SQLcl and SQL*Plus return an empty string whenever null occurs as a result of a SQL SELECT statement.

However, you can use SET NULL to specify a different string to be returned. Here I specified that the string null should be returned.

Incorrect Argument Count

Calling ATAN2() without passing any arguments returns an error:

SELECT ATAN2()
FROM DUAL;

Result:

Error starting at line : 1 in command -
SELECT ATAN2()
FROM DUAL
Error at Command Line : 1 Column : 8
Error report -
SQL Error: ORA-00909: invalid number of arguments
00909. 00000 -  "invalid number of arguments"
*Cause:    
*Action:

And passing the wrong number of arguments results in an error:

SELECT ATAN2(1)
FROM DUAL;

Result:

Error starting at line : 1 in command -
SELECT ATAN2(1)
FROM DUAL
Error at Command Line : 1 Column : 8
Error report -
SQL Error: ORA-00909: invalid number of arguments
00909. 00000 -  "invalid number of arguments"
*Cause:    
*Action: