What is the syntax for using the quarter function in Databricks SQL to extract the quarter of the year from a given date or timestamp?
The syntax for using the `quarter` function in Databricks SQL to extract the quarter of the year from a given date or timestamp is:

`quarter(expr)`

Here, `expr` is a DATE or TIMESTAMP expression. The function returns an INTEGER value in the range 1 to 4 representing the quarter of the year. For example, the query `SELECT quarter('2016-08-31');` would return `3`, indicating that August 31, 2016 falls in the third quarter of the year.