Programonic

Browse languages

PythonReadable code for automation, data, and first programs.TutorialCLearn memory, pointers, and efficient systems programming.TutorialC++Build fast applications with modern types and classes.TutorialJavaUnderstand object oriented programs and the JVM.TutorialJavaScriptAdd behavior to the web and build applications.TutorialTypeScriptJavaScript with static types for dependable code.Tutorial
↑ ↓ to move · Enter to open · Escape to close
Tutorials/SQL

SQL tutorial

Query and organize relational data.

11 lessonsExamples and guided walkthroughs
Start learning View examples

Course contents

11 lessons

Programming fundamentals

01

SQL SELECT

Read rows from a table.

02

SQL Aggregates and GROUP BY

Summarize many rows into one row per group.

03

SQL Joins

Combine rows from two tables that share a key.

04

SQL INSERT, UPDATE, and DELETE

Add, change, and remove rows, then check the result.

Database systems

05

SQL: constraints keep the data valid

Use PRIMARY KEY, NOT NULL, UNIQUE, CHECK, and REFERENCES so the database itself rejects bad rows.

06

SQL: transactions with COMMIT and ROLLBACK

Move money between two accounts so that both updates happen or neither does.

07

SQL: normalization removes repeated facts

Split a table that repeats a customer's city on every row into two tables and see why one update is enough.

08

SQL: subqueries and common table expressions

Compare each row with a group average, and name an intermediate result with WITH.

09

SQL: window functions for running totals and ranks

Compute a running total and a rank within each group without collapsing the rows.

10

SQL: views and triggers

Name a reusable query as a view and record price changes automatically with a trigger.

11

SQL: a unique index and the system catalog

Enforce uniqueness with an index and look up the index in the database's own catalog.