# **CONVERT**

## **Function Description**

The CONVERT() function converts a value to the specified data type or character set.

## **Grammar Structure**

```text
> CONVERT(value, type)

```

or:

```text
> CONVERT(value USING charset)
```

## **Related Parameters**

| Parameters | Description |
| ---- | ---- |
| value | Required parameters, value to be converted |
| datatype | Required parameters, target data type |
| charset | Required parameters, target character set |

Currently, `convert` can be converted as follows:

* Conversion between numeric types mainly includes SIGNED, UNSIGNED, FLOAT, DOUBLE types
* Numeric type to character CHAR type conversion
* Convert character types with numeric format to numeric type (negative numbers need to be converted to SIGNED)

## **Example**

```text
mysql> select convert(150,char);
+-------------------------+
| cast(150 as char) |
+-------------------------+
| 150 |
+-------------------------+
1 row in set (0.01 sec)
```

```text
CREATE TABLE t1(a tinyint);
INSERT INTO t1 VALUES (127);

mysql> SELECT 1 FROM
  -> (SELECT CONVERT(t2.a USING UTF8) FROM t1, t1 t2 LIMIT 1) AS s LIMIT 1;
+------+
| 1 |
+------+
| 1 |
+------+
1 row in set (0.00 sec)
```

## **limit**

* Non-numeric character types cannot be converted to numeric type
* The numerical type and character type of the date format cannot be converted to Date type
* Date, Datetime type cannot be converted to character type
* Date and Datetime cannot convert each other