January 20, 2021

# SQL Cheat Sheet — SQL Reference Guide for Data Analysis

Whether you’re learning SQL through one of our interactive SQL courses or by some other means, it can be really helpful to have a SQL cheat sheet.

Bookmark this article, or download and print the PDF, and keep it handy for quick reference the next time you’re writing an SQL query!

Our SQL cheat sheet goes a bit more in-depth than this handwritten one!

Need to brush up on your SQL before you’re ready for the cheat sheet? Check out our interactive online SQL Fundamentals course, read about why you should learn SQL, or do some research about SQL certifications and whether you’ll need one.

## SQL Basics

SQL stands for Structured Query Language. It is a system for querying — requesting, filtering, and outputting — data from relational databases.

Developed in the 1970s, SQL was originally called SEQUEL. For this reason, today it is sometimes pronounced “Sequel” and sometimes pronounced “S.Q.L.” Either pronunciation is acceptable

Although there are many “flavors” of SQL, SQL in some form can be used for querying data from most relational database systems, including MySQL, SQLite, Oracle, Microsoft SQL Server, PostgreSQL, IBM DB2, Microsoft Azure SQL Database, Apache Hive, etc. databases.

## SQL Cheat Sheet: Fundamentals

#### Performing calculations with SQL

Performing a single calculation:
`SELECT 1320+17;`

Performing multiple calculations:
`SELECT 1320+17, 1340-3, 7*191, 8022/6;`

Performing calculations with multiple numbers:
`SELECT 1*2*3, 1+2+3;`

Renaming results:
`SELECT 2*3 AS mult, 1+2+3 AS nice_sum;`

#### Selecting tables, columns, and rows:

Remember: The order of clauses matters in SQL. SQL uses the following order of precedence: `FROM`, `SELECT`, `LIMIT`.

Display the whole table:

``````SELECT *
FROM table_name;``````

Select specific columns from a table:

``````SELECT column_name_1, column_name_2
FROM table_name;``````

Display the first 10 rows on a table:

``````SELECT *
FROM table_name
LIMIT 10;``````

``````-- First comment
SELECT column_1, column_2, column_3 -- Second comment
FROM table_name; -- Third comment``````

``````/*
This comment
spans over
multiple lines
*/
SELECT column_1, column_2, column_3
FROM table_name;``````

## SQL Intermediate: Joins & Complex Queries

Many of these examples use table and column names from the real SQL databases that learners work with in our interactive SQL courses. For more information, sign up for a free account and try one out!

#### Joining data in SQL:

Joining tables with INNER JOIN:

``````SELECT column_name_1, column_name_2 FROM table_name_1
INNER JOIN table_name_2 ON table_name_1.column_name_1 = table_name_2.column_name_1;``````

Joining tables using a LEFT JOIN:

``````SELECT * FROM facts
LEFT JOIN cities ON cities.facts_id = facts.id;``````

Joining tables using a RIGHT JOIN:

``````SELECT f.name country, c.name city
FROM cities c
RIGHT JOIN facts f ON f.id = c.facts;``````

Joining tables using a FULL OUTER JOIN:

``````SELECT f.name country, c.name city
FROM cities c
FULL OUTER JOIN facts f ON f.id = c.facts_id;``````

Sorting a column without specifying a column name:

``````SELECT name, migration_rate FROM FACTS
ORDER BY 2 desc; -- 2 refers to migration_rate column``````

Using a join within a subquery, with a limit:

``````SELECT c.name capital_city, f.name country
FROM facts f
INNER JOIN (
SELECT * FROM cities
WHERE capital = 1
) c ON c.facts_id = f.id
LIMIT 10;``````

Joining data from more than two tables:

``````SELECT [column_names] FROM [table_name_one]
[join_type] JOIN [table_name_two] ON [join_constraint]
[join_type] JOIN [table_name_three] ON [join_constraint]
...
...
...
[join_type] JOIN [table_name_three] ON [join_constraint]``````

#### Other common SQL operations:

Combining columns into a single column:

``````SELECT
album_id,
artist_id,
"album id is " || album_id col_1,
"artist id is " || artist_id col2,
album_id || artist_id col3
FROM album LIMIT 3;``````

Matching part of a string:

``````SELECT
first_name,
last_name,
phone
FROM customer
WHERE first_name LIKE "%Jen%";``````

Using if/then logic in SQL with CASE:

``````CASE
WHEN [comparison_1] THEN [value_1]
WHEN [comparison_2] THEN [value_2]
ELSE [value_3]
END
AS [new_column_name]``````

Using the WITH clause:

``````WITH track_info AS
(
SELECT
t.name,
ar.name artist,
al.title album_name,
FROM track t
INNER JOIN album al ON al.album_id = t.album_id
INNER JOIN artist ar ON ar.artist_id = al.artist_id
)
SELECT * FROM track_info
WHERE album_name = "Jagged Little Pill";``````

Creating a view:

``````CREATE VIEW chinook.customer_2 AS
SELECT * FROM chinook.customer;``````

Dropping a view:

``DROP VIEW chinook.customer_2;``

Selecting rows that occur in one or more SELECT statements:

``````[select_statement_one]
UNION
[select_statement_two];``````

Selecting rows that occur in both SELECT statements:

``````SELECT * from customer_usa
INTERSECT
SELECT * from customer_gt_90_dollars;``````

Selecting rows that occur in the first SELECT statement but not the second SELECT statement:

``````SELECT * from customer_usa
EXCEPT
SELECT * from customer_gt_90_dollars;``````

Chaining WITH statements:

``````WITH
usa AS
(
SELECT * FROM customer
WHERE country = "USA"
),
last_name_g AS
(
SELECT * FROM usa
WHERE last_name LIKE "G%"
),
state_ca AS
(
SELECT * FROM last_name_g
WHERE state = "CA"
)
SELECT
first_name,
last_name,
country,
state
FROM state_ca``````

## Important Concepts and Resources:

#### Reserved words

Reserved words are words that cannot be used as identifiers (such as variable names or function names) in a programming language, because they have a specific meaning in the language itself. Here is a list of reserved words in SQL.

Click on the button below to download the cheat sheet (PDF, 3 MB, color).

Looking for more than just a quick reference? Dataquest’s interactive SQL courses will help you get hands-on with SQL as you learn to build the complex queries you’ll need to write for real-world data work.

### Learn SQL the right way!

• Write real queries
• Work with real data

Why passively watch video lectures when you can learn by doing?