SQL Tutorial

Introduction

SQL stands for Structured Query Language which is used to retrieve and manipulate data in Relational Database Management System (RDBMS). Relational database stores data in the form of tables. The tables are having columns and rows. SQL query can be used across a variety of databases such as SQL Server, Oracle, DB2, Access, Sybase, My SQL, MongoDB. Initially it was called SEQUEL (Structured English Query Language) and developed at IBM by Donald Chamberlin and Raymond Boyce in 1970s. it became a standard of American National Standard Institute (ANSI) in 1986 and of the International Organisation for Standardization (ISO) in 1987.

SQL Queries or statements are broadly categorised in to 3 types:

• DDL – Data Definition Language – CREATE, ALTER, DROP, COMMENT, RENAME
• DML – Data Manipulation Language – SELECT, INSERT, UPDATE, DELETE
• DCL – Data Control Language – GRANT, REVOKE

DDL Statements
CREATE TABLE	Creates a table
CREATE TABLE AS	Create a table from skeletal definition and data of another table
ALTER TABLE	Add, Changes, Delete columns in a table , rename a table
DROP TABLE	Deletes a Table
COMMENT	Add Comments to the Data Dictionary

DML Statements
SELECT Statement	Fetches Records from a table
INSERT Statement	Inserts Records into a table
UPDATE Statement	Updates Records in a table
DELETE Statement	Delete records from a Table
TRUNCATE Statement	Delete all records from a Table
DCL Statements
GRANT Statement	Provides access or privileges on database objects to users
REVOKE Statement	Removes access or privileges given to user on database objects

SQL Datatypes:	SQL Constraints:
Numeric Datatypes	NOT NULL
Character Datatypes	UNIQUE
Date and Time Datatypes	PRIMARY KEY
Binary Datatypes	FOREIGN KEY
Miscellaneous Datatypes	CHECK
	DEFAULT

SQL Transactions:
Transaction Control Commands:	Properties of Transaction:
BEGIN TRAN	ATOMICITY
SAVE POINT	CONSISTENCY
COMMIT TRAN	ISOLATION
ROLLBACK TRAN	DURABILITY

SQL Operators:	SQL Functions:
Relational Operators	Aggregate Functions:
Arithmetic Operators	Scalar Functions:
Comparison Operators	DATE Function:
Logical Operators	STRING Function:
Set Operators	NUMERIC Function:

SQL Clauses:	SQL Conditions:
DISTINCT Clause	AND Condition
FROM Clause	OR Condition
WHERE Clause	IN Condition
ORDER BY Clause	LIKE Condition
GROUP BY Clause	NOT Condition
HAVING Clause	AND & OR Condition
WITH Clause	IS NULL Condition
AS Clause	IS NOT NULL Condition
TOP Clause	EXISTS Condition
	BETWEEN Condition

SQL Joins:	SQL Keys:
LEFT JOIN	Primary Key
RIGHT JOIN	Unique Key
FULL JOIN	Foreign Key
INNER JOIN	Composite/Compound Key
OUTER JOIN	Alternate Key
SELF JOIN	Super Key
CROSS JOIN	Candidate Key

ADVANCED SQL:
SQL VIEWS
SQL INDEXES
SQL SEQUENCES
SQL ALIASES
SQL SUBQUERIES
SQL TUNING
SQL INJECTION