Contents

Introduction

SQL or Structured Query Language is the main language used to create, modify, retrieve and manipulate data in relational database management systems. SQL comes in several parts:

• The Data Definition Language (DDL) is used to create and delete the structures that will contain the data, in relational database terms, it allows you to create and delete tables;
• The Data Manipulation Language (DML) allows you to insert, update, retrieve and delete data;
• Data Control Language (DCL) is the part of SQL that deals with access control or permissions.

The most used part of SQL is the DML. This is the part of SQL that deals with the SELECT, INSERT, UPDATE and DELETE statements.

DML

SELECT statement

JOINs

Cartesian product (CROSS JOIN)

(FULL) OUTER JOIN

LEFT OUTER JOIN

RIGHT OUTER JOIN

INNER JOIN

NATURAL JOIN

GROUP BY

HAVING

Subqueries

Correlated subqueries

INSERT statement

DELETE statement

UPDATE statement