What is the use of LENGTH in SQL. You may answer with reference to following CTE Query

```
WITH ShowMessage(STATEMENT, LENGTH)
AS
(
SELECT STATEMENT = CAST('I Like ' AS VARCHAR(300)), LEN('I Like ') 
UNION ALL
SELECT
      CAST(STATEMENT + 'Stackoverflow! ' AS VARCHAR(300))
      , LEN(STATEMENT) FROM ShowMessage
WHERE LENGTH < 300
)
SELECT STATEMENT, LENGTH FROM ShowMessage

```