Selecting tables, columns, and rows:
SQL Cheat Sheet: Fundamentals
Performing calculations with SQL
Display the whole table:
SELECT
FROM
*
table_name;
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;
SELECT
FROM
Remember: The order of clauses matters in SQL. SQL
uses the following order of precedence: FROM, SELECT,
LIMIT.
column_name_1, column_name_2
table_name;
Display the first 10 rows on a table:
SELECT
FROM
LIMIT
*
table_name;
10
;
Adding comments to your SQL queries
Adding single-line comments:
SELECT
FROM
-- First comment
column_1, column_2, column_3 -- Second comment
table_name; -- Third comment
Adding block comments:
SELECT
FROM
/*
This comment
spans over
multiple lines
*/
column_1, column_2, column_3
table_name;
Select specific columns from a table:
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!
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 data in SQL:
SQL Intermediate:
Joins & Complex Queries
Joining tables with INNER JOIN:
SELECT * FROM facts
LEFT JOIN cities ON cities.facts_id = facts.id;
Joining tables using a LEFT JOIN:
SELECT f.name country, c.name city
FROM cities c
RIGHT JOIN facts f ON f.id = c.facts;
Joining tables using a RIGHT JOIN:
SELECT f.name country, c.name city
FROM cities c
FULL OUTER JOIN facts f ON f.id = c.facts_id;
Joining tables using a FULL OUTER JOIN:
SELECT name, migration_rate FROM FACTS
ORDER BY 2 desc; -- 2 refers to migration_rate column
Sorting a column without specifying a column name:
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
INNER 10
Using a join within a subquery, with a limit:
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]
Joining data from more than two tables:
