# CAST

## Syntax

```
cast (input as type)
```

## Description

将 input 转成 指定的 type 

## BIGINT type 

### Syntax

``` cast (input as BIGINT) ```

### Description

将当前列 input 转换为 BIGINT 类型

### Examples

1. 转常量，或表中某列

```
mysql> select cast (1 as BIGINT);
+-------------------+
| CAST(1 AS BIGINT) |
+-------------------+
|                 1 |
+-------------------+
```

2. 转导入的原始数据

```
curl --location-trusted -u root: -T ~/user_data/bigint -H "columns: tmp_k1, k1=cast(tmp_k1 as BIGINT)"  http://host:port/api/test/bigint/_stream_load
```

*注：在导入中，由于原始类型均为String，将值为浮点的原始数据做 cast的时候数据会被转换成 NULL ，比如 12.0 。Doris目前不会对原始数据做截断。*

如果想强制将这种类型的原始数据 cast to int 的话。请看下面写法：

```
curl --location-trusted -u root: -T ~/user_data/bigint -H "columns: tmp_k1, k1=cast(cast(tmp_k1 as DOUBLE) as BIGINT)"  http://host:port/api/test/bigint/_stream_load

mysql> select cast(cast ("11.2" as double) as bigint);
+----------------------------------------+
| CAST(CAST('11.2' AS DOUBLE) AS BIGINT) |
+----------------------------------------+
|                                     11 |
+----------------------------------------+
1 row in set (0.00 sec)
```