SQL Tutorial Part2

. 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                           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

         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
 

DQL - Data Query Language:

      Command                    Description

      SELECT                 Retrieves certain records from one or more tables 
 
SQL –Syntax

SQL is followed by unique set of rules and guidelines called Syntax. This tutorial gives you a
quick start with SQL by listing all the basic SQL Syntax:

All the SQL statements start with any of the keywords like SELECT, INSERT, UPDATE, DELETE,
ALTER, DROP, CREATE, USE, SHOW and all the statements end with a semicolon (;).

Important point to be noted is that SQL is case insensitive which means SELECT and select have same meaning in SQL statements but MySQL make difference in table names. So if you are working with MySQL then you need to give table names as they exist in the database.

SQL SELECT Statement:

SELECT column1, column2....columnN
FROM     table_name;

SQL DISTINCT Clause:

SELECT DISTINCT column1, column2....columnN
FROM     table_name;

SQL WHERE Clause:

SELECT column1, column2....columnN
FROM     table_name
WHERE  CONDITION;

SQL AND/OR Clause:

SELECT column1, column2....columnN
FROM     table_name
WHERE  CONDITION-1 {AND|OR} CONDITION-2;

SQL IN Clause:

SELECT column1, column2....columnN
FROM     table_name
WHERE  column_name IN (val-1, val-2,...val-N);


SQL BETWEEN Clause:

SELECT column1, column2....columnN
FROM    table_name
WHERE   column_name BETWEEN val-1 AND val-2;

SQL Like Clause:

SELECT column1, column2....columnN
FROM    table_name
WHERE  column_name LIKE { PATTERN };

SQL ORDER BY Clause:

SELECT column1, column2....columnN
FROM    table_name
WHERE  CONDITION
ORDER BY column_name {ASC|DESC};

SQL GROUP BY Clause:

SELECT SUM(column_name)
FROM    table_name
WHERE  CONDITION
GROUP BY column_name;

SQL COUNT Clause:

SELECT COUNT(column_name)
FROM    table_name
WHERE  CONDITION;

SQL HAVING Clause:

SELECT SUM(column_name)
FROM    table_name
WHERE  CONDITION
GROUP BY column_name
HAVING (arithematic function condition);

SQL CREATE TABLE Statement:

CREATE TABLE table_name(
column1 datatype,
column2 datatype,
column3 datatype,
.....
columnN datatype,
PRIMARY KEY( one or more columns )
);

SQL DROP TABLE Statement:

DROP TABLE table_name;

SQL CREATE INDEX Statement :

CREATE UNIQUE INDEX index_name
ON table_name ( column1, column2,...columnN);

SQL DROP INDEX Statement :

ALTER TABLE table_name
DROP INDEX index_name;

SQL DESC Statement :

DESC table_name;

SQL TRUNCATE TABLE Statement:

TRUNCATE TABLE table_name;

SQL ALTER TABLE Statement:

ALTER TABLE table_name {ADD|DROP|MODIFY} column_name {data_ype};

SQL ALTER TABLE Statement (Rename) :

ALTER TABLE table_name RENAME TO new_table_name;

SQL INSERT INTO Statement:

INSERT INTO table_name( column1, column2....columnN)
VALUES ( value1, value2....valueN);

SQL UPDATE Statement:

UPDATE table_name
SET column1 = value1, column2 = value2....columnN=valueN
 [ WHERE  CONDITION ];

SQL DELETE Statement:

DELETE FROM table_name
WHERE  {CONDITION};

SQL CREATE DATABASE Statement:

CREATE DATABASE database_name;

SQL DROP DATABASE Statement:

DROP DATABASE database_name;

SQL USE Statement:

USE DATABASE database_name;

SQL COMMIT Statement:

COMMIT;

SQL ROLLBACK Statement:

ROLLBACK;