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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

  • xNaN,返回 NaN
  • x 为正无穷,返回 π/2(约 1.570796326794897)
  • x 为负无穷,返回 -π/2(约 -1.570796326794897)
  • xNULL,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 |
+------------------------------+