SQL Introduction

SQL is a database computer language designed for the retrieval and management of data in relational database. SQL stands for Structured Query Language.

SQL

1. Allows users to access data in relational database management systems.
2. Allows users to describe the data.
3. Allows users to define the data in database and manipulate that data.
4. Allows to embed within other languages using SQL modules, libraries & pre-compilers.
5. Allows users to create and drop databases and tables.
6. Allows users to create view, stored procedure, functions in a database.
7. Allows users to set permissions on tables, procedures, and views

SQL Commands:

The standard SQL commands to interact with relational databases are CREATE, SELECT, INSERT, UPDATE, DELETE and DROP. These commands can be classified into groups based on their nature:

DDL – Data Definition Language:

Command	Description
CREATE	Creates a new table, a view of a table, or other object in database
ALTER	Modifies an existing database object, such as a table.
DROP	Deletes an entire table, a view of a table or other object in the database.

DML – Data Manipulation Language:

Command	Description
SELECT	Retrieves certain records from one or more tables
INSERT	Creates a record
UPDATE	Modifies records
DELETE	Deletes records

DCL – Data Control Language:

Command	Description
GRANT	Gives a privilege to user
REVOKE	Takes back privileges granted from user