# **LEFT()**

## **Function Description**

The `LEFT()` function returns the leftmost length character in the *str* string. If the *str* or *len* parameter is `NULL`, the `NULL` value is returned.

## **Function Syntax**

```text
> LEFT(str,len)
```

## **Parameter definition**

| Parameters | Description |
| ---- | ---- |
| str | Required parameters. The string to extract the substring. |
| len | Required parameters. is a positive integer that specifies the number of characters to be returned from the left. <br>If *len* is 0 or negative, the LEFT function returns an empty string. <br>If *len* is greater than the length of the *str* string, the LEFT function returns the entire *str* string. |

## **Example**

```text
mysql> select left('abcde', 3) from dual;
+---------------------+
| left(abcde, 3) |
+---------------------+
| abc |
+---------------------+
1 row in set (0.00 sec)

drop table if exists t1;
CREATE TABLE t1 (str VARCHAR(100) NOT NULL, len INT);
insert into t1 values('abcdefghijklmn',3);
insert into t1 values(' ABCDEFGH123456', 3);
insert into t1 values('ABCDEF GHIJKLMN', 20);
insert into t1 values('ABCDEFGHijklmn ', -1);
insert into t1 values('ABCDEFGH123456', -35627164);
insert into t1 values('', 3);
mysql> select left(str, len) from t1;
+------------------------+
| left(str, len) |
+------------------------+
| abc |
| A |
| ABCDEF GHIJKLMN |
| |
| |
| |
+------------------------+
6 rows in set (0.01 sec)

mysql> select left('sdfsdfsdfsdf', len) from t1;
+------------------------------+
| left(sdfsdfsdfsdf, len) |
+------------------------------+
| sdf |
| sdf |
| sdfsdfsdfsdfsdf |
| |
| |
| sdf |
+------------------------------+
6 rows in set (0.01 sec)
```