SQL Server 2005

 SQL stands for Structured Query Language. This language is used to retrieve,update,insert and delete data from an database object called Table.A table consists of rows and columns.

In fact whole SQL is based on RDBMS(Relational Database Management System).

At this point of time I am going to show some basic queries used in SQL.Although these are very basic but very much crucial in day to day job.

Suppose there is a table "Customer" which is used o store the Name of customer,Phone No.,Address, State,Country and Product.The table will look like,

CustomerID	CustomerName	PhoneNO	Address	State	Country	Product
1	John	10000	Luciana	Alabama	USA	Watch
2	Mr. Naidu	20000	Lucknow	U.P	India	TV
3	Miss. Filomena	30000	Chennai	Kerela	India	Book
4	Mr. Meverick	50000	Singapore	Singapore	Singapore	Computer
5	Mr. Gaurav	60000	Gorakhpur	U.P	India	Cloth

Suppose  a client needs to get a report of the his/her customer and you are a SQL expert. So you will write a query like

SELECT * FROM  Customer

This query will fetch you all the data of the  table.But most of the time we need some specific data which may come from a single table or from a combination of one or more table.For the time being I am going to explain how to fetch data from a single table with some given constraints.

CustomerID	CustomerName	PhoneNO	Address	State	Country	Product
1	John	10000	Luciana	Alabama	USA	Watch
2	Mr. Naidu	20000	Lucknow	U.P	India	TV
3	Miss. Filomena	30000	Chennai	Kerela	India	Book
4	Mr. Meverick	50000	Singapore	Singapore	Singapore	Watch
5	Mr. Gaurav	60000	Gorakhpur	U.P	India	Watch

If you want to get the info about the customers buying Watch then you should write like

SELECT * FROM Customer WHERE Product= 'Watch'

This will fetch you

CustomerID	CustomerName	PhoneNO	Address	State	Country	Product
1	John	10000	Luciana	Alabama	USA	Watch
4	Mr. Meverick	50000	Singapore	Singapore	Singapore	Watch
5	Mr. Gaurav	60000	Gorakhpur	U.P	India	Watch