# STARTS_WITH

The STARTS_WITH function returns a boolean value indicating whether a keyword string begins with a specified prefix string.

## Syntax

`STARTS_WITH(str, prefix)`

### Parameters

#### str

The string expression to evaluate. If this value is `null`, the function returns `null`.

#### prefix

The string expression to check as the prefix. If this value is `null`, the function returns `null`.

## Examples

Checks whether each employee's last name begins with the letter "B" and adds the result as a new column.

```esql
FROM employees
| KEEP last_name
| EVAL ln_S = STARTS_WITH(last_name, "B")
```