# substring({str} FROM {start} FOR {length})

Returns a substring from string *str* that begins with the character at the *start* position.

:::note
The substring function isn’t supported in Analytics Studio. An error occurs when the function is used in the UI. The function is available using the Query API. For more information, see [Query CRM Analytics Data with the Query API](https://developer.salesforce.com/docs/atlas.en-us.bi_dev_guide_rest.meta/bi_dev_guide_rest/bi_rest_api_query_data.htm).
:::

- `start`

  - : Required. The starting position of the substring. This is the first character of the substring. The value can be positive or negative. If positive, the position is taken from the beginning of the string. If negative, the position is taken from the end of the string.

- `length`

  - : Optional. The length of the substring, beginning at the *start* position. If no value is provided, `substring()` extracts characters from the *start* position through the end of the string.

## Example

This example extracts the first three letters from each City field.

```nolang
SELECT City, SUBSTRING(City FROM 1 FOR 3) as CityCode FROM "Superstore"
GROUP BY City LIMIT 5;

```

| City        | CityCode |
| ----------- | -------- |
| Aberdeen    | Abe      |
| Abilene     | Abi      |
| Akron       | Akr      |
| Albuquerque | Alb      |
| Alexandria  | Ale      |