This document provides an overview of SQL and MySQL fundamentals including: - MySQL is a popular open source relational database management system commonly used for web applications. It includes tools like PHPMyAdmin. - Key SQL concepts are explained such as databases, tables, columns, rows, primary keys, foreign keys, and indexes. - The main SQL languages - DML, DDL, DCL, TCL - are defined along with common commands in each. - Basic SQL functions are also covered including aggregate, scalar, and join functions.

1. SQL – Pocket Guide
-By Santhosh Kumar

2. MySQL standards
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MySQL is the most popular Open Source Relational SQL database management
system.
MySQL is one of the best RDBMS being used for developing web based software
applications.
MySQL database application should be installed on your web server. MySQL is very
popular so you will have no problem in finding a web host that offers MySQL.
Most web host also offer a (GUI) Graphical user interface application such as
PHPMyAdmin for working with MySQL databases.

3. Terminology
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Database: A database is a collection of tables, with related data.
Table: A table is a matrix with data. A table in a database looks like a simple
spreadsheet.
Column: One column (data element) contains data of one and the same kind, for
example the column postcode.
Row: A row (= tuple, entry or record) is a group of related data, for example the
data of one subscription.
Redundancy: Storing data twice, redundantly to make the system faster.
Primary Key: A primary key is unique. A key value can not occur twice in one table.
With a key you can find at most one row.
Foreign Key: A foreign key is the linking pin between two tables.
Compound Key: A compound key (composite key) is a key that consists of multiple
columns, because one column is not sufficiently unique.
Index: An index in a database resembles an index at the back of a book.
Referential Integrity: Referential Integrity makes sure that a foreign key value
always points to an existing row.

4. What is – DML, DDL, DCL and TCL
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DML
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DML is abbreviation of Data Manipulation Language. It is used to retrieve,
store, modify, delete, insert and update data in database.
DDL
DDL is abbreviation of Data Definition Language. It is used to create and
modify the structure of database objects in database.
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DCL
DCL is abbreviation of Data Control Language. It is used to create roles,
permissions, and referential integrity as well it is used to control access to database
by securing it.
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TCL
TCL is abbreviation of Transactional Control Language. It is used to manage
different transactions occurring within a database.

5. Commands
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DDL : CREATE, ALTER, DROP
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DML : INSERT, UPDATE, DELETE
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DCL : GRANT, REVOKE
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TCL : COMMIT, SAVE POINT, ROLLBACK
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DQL : SELECT

6. Basic SQl Commands
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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
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

7. Basic SQL Functions
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SQL Aggregate Functions
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SQL aggregate functions return a single value, calculated from values in a column.
AVG() - Returns the average value
COUNT() - Returns the number of rows
FIRST() - Returns the first value
LAST() - Returns the last value
MAX() - Returns the largest value
MIN() - Returns the smallest value
SUM() - Returns the sum

8. Basic SQL Functions
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SQL Scalar functions
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SQL scalar functions return a single value, based on the input value.
UCASE() - Converts a field to upper case
LCASE() - Converts a field to lower case
MID() - Extract characters from a text field
LEN() - Returns the length of a text field
ROUND() - Rounds a numeric field to the number of decimals specified
NOW() - Returns the current system date and time
FORMAT() - Formats how a field is to be displayed

9. Joins
SQL joins are used to combine rows from two or more tables
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INNER JOIN: Returns all rows when there is at least one match in BOTH tables
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LEFT JOIN: Return all rows from the left table, and the matched rows from the
right table
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RIGHT JOIN: Return all rows from the right table, and the matched rows from the
left table
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FULL JOIN: Return all rows when there is a match in ONE of the tables

10. Many Thanks
For More : Find in Google 
Many Thanks
Santhosh Kumar