Initially developed at IBM in the early 1970s, SQL was formalized by the American National Standards Institute (ANSI) in 1986. Since then the SQL standard has been revised seven times.
SQL consists of a data definition language (DDL) and a data manipulation language (DML). The DDL is used to create, delete, and alter the structure of a table and other database objects. The DML is used to insert, retrieve, and update data in a table or tables.
Many database vendors implement a version of SQL that is not 100% compliant with the standard. They often add unique features to their SQL, resulting in an SQL dialect.
This book is for you if you want to learn SQL the easy way.