ATAN
描述
返回x
的反正切值,x
为弧度值。
语法
ATAN(<x>)
参数
参数 | 说明 |
---|---|
<x> | 需要被计算反正切的值 |
返回值
参数 x 的反正切值
特殊情况
- 当
x
为NaN
,返回NaN
- 当
x
为正无穷,返回π/2
(约 1.570796326794897) - 当
x
为负无穷,返回-π/2
(约 -1.570796326794897) - 当
x
为NULL
,返回NULL
举例
select atan(0);
+-----------+
| atan(0.0) |
+-----------+
| 0 |
+-----------+
select atan(2);
+--------------------+
| atan(2.0) |
+--------------------+
| 1.1071487177940904 |
+--------------------+
select atan(cast('nan' as double));
+-----------------------------+
| atan(cast('nan' AS DOUBLE)) |
+-----------------------------+
| NaN |
+-----------------------------+
select atan(cast('inf' as double));
+-----------------------------+
| atan(cast('inf' AS DOUBLE)) |
+-----------------------------+
| 1.570796326794897 |
+-----------------------------+
select atan(cast('-inf' as double));
+------------------------------+
| atan(cast('-inf' AS DOUBLE)) |
+------------------------------+
| -1.570796326794897 |
+------------------------------+