SQL Functions: return a single value
• AVG() - Returns the average value
• COUNT() - Returns the number of rows
• MAX() - Returns the largest value
• MIN() - Returns the smallest value
• SUM() - Returns the sum
Select avg(column_name) from table_name
Select count(*) from table_name
Select count(distinct customerid) as numberofcustomer from orders
Select first(column_name) from table_name
Select max(column_name) from table_name
Select max(price) as highestprice from products
Select min(column_name) from table_name
Select sum(column_name) from table_name