Functions, sorting, and grouping

Introduction to Snowflake SQL

George Boorman

Senior Curriculum Manager, DataCamp

String functions - INITCAP

Syntax: INITCAP( <expr> )

Capitalize each word in a string

SELECT INITCAP(category) AS capitalized_category 
FROM pizza_type

Capitalized pizza names result

String functions - CONCAT

Combines the expressions

Syntax:

CONCAT( <expr1> [ , <exprN> ... ] )

Before Concat:

Before concatenation category column

Combining category with ' - Pizza'

SELECT CONCAT(category, ' - Pizza') 
  AS pizza_category 
FROM pizza_type

After Concat:

Before concatenation category column

DATE & TIME functions

CURRENT_DATE() or CURRENT_DATE
CURRENT_TIME() or CURRENT_TIME

SELECT CURRENT_DATE

SELECT CURRENT_TIME

Current date result

Current time result

EXTRACT

Syntax

EXTRACT( <date_or_time_part> FROM <date_or_time_expr> )
- <date_or_time_part> - year, month, day, weekday, etc.

SELECT EXTRACT(MONTH FROM order_date) AS order_month,
    COUNT(*) AS num_orders
FROM orders
GROUP BY order_month

Number of orders per month

SORTING and GROUPING

SORTING: ORDER BY
GROUPING: GROUP BY
- Snowflake: GROUP BY ALL

GROUP BY ALL

GROUP BY column1, column2

SELECT 
    pizza_type_id,
    size,
    AVG(price) AS average_price
FROM 
    pizzas
GROUP BY
    pizza_type_id, -- explicit columns
    size
ORDER BY 
    pizza_type_id, average_price DESC

GROUP BY ALL

SELECT 
    pizza_type_id,
    size,
    AVG(price) AS average_price
FROM 
    pizzas
GROUP BY ALL -- Don't specify columns 
ORDER BY 
    pizza_type_id, average_price DESC

Summary

Function/keyword	Use
`INITCAP()`	Capitalize each word in a string
`CONCAT()`	Combine multiple strings
`CURRENT_DATE`	Get the current date
`CURRENT_TIME`	Get the current time
`EXTRACT`	Pull a date/time element, e.g., `month` from a date
`ORDER BY`	Sort query results
`GROUP BY ALL`	Group query by all (non-aggregated) columns

Let's practice!

Introduction to Snowflake SQL