SQL is a standard language for accessing databases.
Keep in mind that..
SQL is not case sensitive
Some database systems require a semicolon at the end of each SQL statement.
SQL can be divided into two parts:
1. The Data Manipulation Language (DML)
The query and update commands are form the DML part of SQL:
SELECT - extracts data from a database
UPDATE - updates data in a database
DELETE - deletes data from a database
INSERT INTO - inserts new data into a database
2. The Data Definition Language (DDL).
The DDL part of SQL permits database tables to be created or deleted. It also define indexes (keys), specify links between tables, and impose constraints between tables. The most important DDL statements in SQL are:
CREATE DATABASE - creates a new database
ALTER DATABASE - modifies a database
CREATE TABLE - creates a new table
ALTER TABLE - modifies a table
DROP TABLE - deletes a table
CREATE INDEX - creates an index (search key)
DROP INDEX - deletes an index
External Links:
http://www.w3schools.com/sql/default.asp