# **ACOS()**

## **函数说明**

ACOS() 函数返回给定数值的余弦（用弧度表示）。

## **函数语法**

```text
> ACOS(number)
```

## **参数释义**

|  参数   | 说明  |
|  ----  | ----  |
| number | 必要参数，可取任意数值数据类型 |

## **示例**

```text
drop table if exists t1;
create table t1(a float,b int);
insert into t1 values(0.5,1);
insert into t1 values(-0.5,-1);

mysql> select acos(a),acos(b) from t1;
+--------------------+-------------------+
| acos(a)            | acos(b)           |
+--------------------+-------------------+
| 1.0471975511965976 |                 0 |
| 2.0943951023931957 | 3.141592653589793 |
+--------------------+-------------------+
2 rows in set (0.01 sec)
```