# CONTAINS

The CONTAINS function returns a boolean value indicating whether a specified keyword substring exists within another string. If either parameter is null, the function returns null.

## Syntax

`CONTAINS(string, substring)`

### Parameters

#### string

The input string to check against. If this value is null, the function returns null.

#### substring

The substring to search for within the input string. If this value is null, the function returns null.

## Examples

Checks whether the substring "ll" is present in the string "hello" and stores the result in a new column.

```esql
ROW a = "hello"
| EVAL has_ll = CONTAINS(a, "ll")
```