In order to compute the standard of a column, SQL uses a function which is AVG(). The main structure of this function is given below:-
If we have to acquire the average of the sales from the given table then the result will be like that:
Boston $1200 Jan-06-2011
San Francisco $200 Jan-07-2011
San Diego $350 Jan-08-2011
Los Angeles $750 Jan-08-2011
The syntax will be as follows:
$625 shows the average calculated by all the columns related to sales. ($1200 + $200 + $350 + $750) / 4.