Snowflake Sql Aggregate Functions & Table Joins

In this article, we explain how to use aggregate functions with Snowflake.

(This article is part of our Snowflake Guide. Use the right-hand menu to navigate.)

What are aggregate functions?

Aggregate functions are those that perform some calculation over all the rows or subsets of rows in a table.

For example, the simplest aggregate function is count(). You could count all the customers in a table using count(*) with no group or where clause. The * tells Snowflake to look at all columns, but you could have put just one column as it means the same thing.

select count(*) from orders

But if you want to count orders over some subset you could, for example, count customers by order type:

select ordertype, count(*) from orders
group by ordertype;

Create some sample data

Let’s create some sample data in order to explore some of these functions. Log into Snowflake and click the Create Database button to create a database called inventory. Next, open the worksheet editor and paste in these two SQL commands:

CREATE TABLE customers
( 
customernumber     varchar(100) PRIMARY KEY, 
customername varchar(50),
phonenumber varchar(50),
postalcode varchar(50),
locale varchar(10),
datecreated date,
email varchar(50)
);
CREATE TABLE orders
( 
customernumber     varchar(100) PRIMARY KEY,
ordernumber varchar(100),
comments varchar(200),
orderdate date,
ordertype varchar(10),
shipdate date,
discount number,
quantity int,
productnumber varchar(50)
)

Then paste in this data. The data looks like this:

insert into customers (customernumber,customername,phonenumber,postalcode,locale,datecreated,email) values ('ee56d97a-fcaa-11ea-ab7a-0ec120e133fc','zopvxqhwocrtsonemrcf','3119110','vqlx','','2020-09-22','');
insert into orders (customernumber,ordernumber,comments,orderdate,ordertype,shipdate,discount,quantity,productnumber) values ('ee56d97a-fcaa-11ea-ab7a-0ec120e133fc','ee56d97b-fcaa-11ea-ab7a-0ec120e133fc','shsyuaraxxftdzooafbg','2020-09-22','sale','2020-10-01','0.7751890540939359','40','ee56d97c-fcaa-11ea-ab7a-0ec120e133fc');