SQL Query Average function syntax

Scenario: Suppose you have a everyday sales table with you and you want to know the average sale happened on a day. Then using this function you can easily get this.

Syntax SELECT AVG(ColumnName) FROM table_name;

So lets suppose i have a 30 day sales data in the table named SALE. And there is a column SalesAmount which depicts the daily sale amount. and If we want to know the average sales happened in that month. We can easily get this using:

SELECT AVG(SalesAmount) FROM SALE;