Avg function in SQL

AVG returns the average of the values in expression.

([All |Distinct]<expression>)

see more infrormation plz visit

Data Types

In SQL data types are four types. String,Numaric,Date/Time and large data types. following table contain all data types used in SQL.



majar data types 

string 
numaric
date and time
large

see more information plz visit

IsNull

The ISNULL function checks an expression for a NULL value and replaces it with a specified replacement value.

select birthdate,
isnull (birthdate,from '01/04/12')as and newdate
from employees
where employeeid =10

see more information plz visit 

Views

A view is something of a virtual table. A view, for the most part, is used just like a table, except that it doesn’t contain any data of its own. The difference between a view and a table is that views are definitions built on top of other tables (or views), and do not hold data themselves. Instead, a view is merely a pre planned mapping and representation of the data stored in tables. You can add SQL functions, WHERE, and JOIN statements to a view and present the data as if the data were coming from one single table.


create view productlist

select productid ,productname 

from products



see more information plz visit 

Alter

The ALTER TABLE statement allows changing the structure of a table after it has been created. New columns can be added with the ADD clause. Existing columns may be removed from a table using the Drop clause.


alter table emploeeys
add salary int


see more information plz visit

Drop

The SQL DROP command is used to remove an object from the database. If you drop a table, all the rows in the table is deleted and the table structure is removed from the database. Once a table is dropped we cannot get it back, so be careful while using RENAME command. When a table is dropped all the references to the table will not be valid.



Drop table employee


see more information plz visit

Check Constraint

CHECK constraints are that they are not restricted to a particular column. They may also check that any combination of column values meets a criterion. The constraint is defined using the same rules that you would use in a WHERE clause. Once the check defined, the database will only insert a new row or update an existing row if the new value satisfies the CHECK constraint. The CHECK constraint is used to ensure data quality.

create table employees
(
imployeeid int check(employeeid >0)

Lname nvarchar(20),
Fname nvarchar(20)

)

see more information plz visit

Forein Key

Foreign keys are both a method of ensuring data integrity and a manifestation of the relationships between tables. When you add a foreign key to a table, you are creating a dependency between the table for which you define the foreign key (the referencing table) and the table your foreign key references (the referenced table). 
The FOREIGN KEY constraint is used to prevent actions that would destroy links between tables.

create table orders
(
orderid int primary key,
orderdate datetime ,
employeeid int refrences employees(employeeid)

)

see more information plz visit

Primary Key

Primary keys are the unique identifiers for each row. They must contain unique values (and hence cannot be NULL). Because of their importance in relational databases 
Primary keys are the most fundamental of all keys and constraints. A table can have a maximum of one primary key. A primary key can consist of one or more fields on a table. When multiple fields are used as a primary key, they are called a composite key.


create table employee
{
empid int primary key,
empname varchar(20),
empLname varchar(20),
}


see more information plz visit 

unique constraint

Once you establish a unique constraint, every value in the named columns must be unique. If you go to update or insert a row with a value that already exists in a column with a unique constraint, SQL Server will raise an error and reject the record.

create table employee
{
empid int unique,
empname varchar(20),
empLname varchar(20),
}

see more information from visit

NOTNULL use in database SQL

This one is pretty simple it states whether the column accepts NULL values or not. When you specify NotNull attribute to column then u cannot give null vale to column or set column as null.

create table emloyee
{
empid int notnull,
empname nvarchar(20) notnull,
empLname nvarchar(20)notnull,
}

see more infromation from plz visit

create table in database SQL

This is the main container for holding data in the database. It can be created through following command.

create table employee
{

empid int,
empname varcahr,
emllaname varchar,
}

Result of this command is to make new object for storing of data name dumyTable.

see more information plz visit 

how to create database in SQL

Create Database means to create new object for storing data of particular thing. As describe in Syntax.

create <objecttype> <objectname>

create database dumydatabase

see more information plz visit 

Union key word use in SQL

union is a special operator we can use to cause two or more queries to generate one result set. All the      union queries must have the same number of columns in the SELECT list. Data type should be same of columns in select queries. By default union operator result is distinct which means same data in column will eliminate.

select employeename from empoyee
union
select suppliername from suppliers

see more information plz visit

Full join

full join are used to all record retrive from tow table .full join retrive data from both side right and left
from the table .full join used for the matching pattern.


select * from employeename
from employee
full join manager
on employee.name =manager.name


see more detail plz visit

Cross join

A CROSS JOIN differs from other joins in that there is no ON operator, and that it joins every record on one side of the JOIN with every record on the other side of the JOIN. In short, you wind up with a Cartesian product of all the records on both sides of the JOIN. The syntax is the same as any other JOIN except that it uses the keyword CROSS (instead of INNER, OUTER), and that it has no ON operator.

select * from employeename
from employee
cross join manager

see more detail plz visit

outer joins left and right

outer joins are, as we have said, inclusive in nature. What specifically gets included depends on which side of the join you have emphasized.

A left outer join includes all the information from the table on the left.

select employename 
from employee
left joint manager

on employee.hussain=manager.shahzad

And a right outer join includes all the information from the table on the right. Let’s put this into practice with a small query so that you can see what I mean.

select employename 
from employee
right joint manager

on employee.hussain=manager.shahzad

see more detail plz visit

Inner join

Inner joins are far and away the most common kind of JOIN. They match records together based on one or more common fields, as do most JOINs, but an INNER JOIN returns only the records where there are matches for whatever field(s) you have said are to be used for the JOIN.

select employname 
from employee
inner join managername
on employee.employname=manager.managername

see more plz visit 

Use Between Key Word

Between used in where clause select range of data between values.

Between is used in that scenario when we want to retrieve data between 2 record or data.

Use Between Key word
select * from employees
where Lastname Between 'shahzad' and 'samejo'

see more detail plz visit

like key word

Like operator used for pattern matching.and Like operator is used in where clause.


select * from employee

where lastname like "%u%"

see more detail plz visit

Top clause

Top key word used to retrieve desired no of rows when table contain hundred or thousand of data.

select top * from employee

Or 
select top * from employee

see more detail plz this link

update command

how to update value in database table.

it used to update existing record in table

update employee

set empid='1' empname="waseem"

where empid='1'

see more detail plz visit

insert value

how to insert value in sql database table.

insert query is used to new record in table .

insert into employee

value(value1,value2,value3)

see more detail plz visit 

using or operator

and operator displays record when all conditions are true.

And operator use like as

select * from employee

where lastname='samejo' and firstname='shahzad'

more detail visit following 

 

 

where clause

how to use where clause in sql.

where key word

select employeeid from orders

where employeeid >2

this is very helpfull query

see more detail visit

how to use distinct key word in sql

The DISTINCT keyword eliminates / filters out duplicate rows from the results of a SELECT statement.

distinct key word 

select count(employeeeid) from orders

select count(distinct employeeid) from orders

this is very helpfull query from me you

more detail visit

select command in SQL

how to select data from database table .

select * from tablename

Most commonly used SQL command is SELECT statement .We use Select query to retrieve data from database.

for more detail visit

what is site collection in sharepoint ?

sharepoint site collection is  logical group of multipel sharepoint site or hierarchical site structure .

for example: site of various team or departments of an organization can be grouped logically in one

site collection.

for more detail visit

what is sharepoint ?

sharepoint is simple idea  to "share document" microsoft developed family of software called "share point".
To perform features like file sharing  .

more detail view