8.2.4 ATAN2
Returns the angle (in radians) that is the inverse tangent of y/x, in the range - to .
In the specification format, y is set to target-data-1, x is set to target-data-2, and the quadrant in which the value of the execution result falls is determined by the signs of y and x.
- Organization of this subsection
(1) Specification format
scalar-function-ATAN2 ::= ATAN2(target-data-1,target-data-2) target-data-1 ::= value-expression target-data-2 ::= value-expression
(2) Explanation of specification format
- target-data-1 and target-data-2:
-
Specifies the numeric data whose inverse tangent of y/x is to be determined.
The following rules apply:
-
Specify target-data-1 and target-data-2 in the form of value expressions. For details about value expressions, see 7.20 Value expression.
-
Specify numeric data for target-data-1 and target-data-2. For details about numeric data, see (1) Numeric data in 6.2.1 List of data types.
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You cannot specify a dynamic parameter by itself for target-data-1 or target-data-2.
-
(3) Rules
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The data type of the execution result is the DOUBLE PRECISION type.
-
The NOT NULL constraint does not apply to the value of the execution result (the null value is allowed).
-
If either target-data-1 or target-data-2 has a null value, the execution result will be a null value.
(4) Example
- Example:
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Specify the values of columns C1 and C2 from table T1 for target-data-1 and target-data-2, and then determine the inverse tangent of y/x.
SELECT ATAN2("C1","C2") FROM "T1"