Help to understand .Net

The SELECT TOP clause is used to specify the number of records to return. The SELECT TOP clause can be very useful on large tables with thousands of records. Returning a large number of records can impact on performance. Example CREATE TABLE [dbo] . [Emp] (       [EmpID] [int] IDENTITY ( 1 , 1 ) NOT NULL,       [EmpName] [varchar] ( 50 ) NULL, ) INSERT INTO EMP ( EmpName ) VALUES ( 'ABC' ) INSERT INTO EMP ( EmpName ) VALUES ( 'CDE' ) INSERT INTO EMP ( EmpName ) VALUES ( 'PQR' ) INSERT INTO EMP ( EmpName ) VALUES ( 'XYZ' ) INSERT INTO EMP ( EmpName ) VALUES ( 'NML' )  With Top Clause SELECT Top 3 Records SELECT Top 3 * FROM Emp Without TOP Clause  SELECT * FROM Emp e1 WHERE ( SELECT COUNT (*) FROM Emp e2 WHERE e2 . EmpID < e1 . EmpID )< 3 Output Emp_ID Emp_Name 1 ABC 2 CDE 3 PQR

REPLACE is used to replace all the occurrences of the given pattern in a string. Example SELECT REPLACE ( 'Hello i am here' , 'H' , 'm' ) -- mello i am mere STUFF used to replace the part of string with some other string. Example   SELECT STUFF ( 'Hello i am here' , 1 , 5 , 'Hi' ) -- Hi i am here

Local temporary table Global temporary table Denoted by # symbol. Denoted by ## symbol. Local temporary tables are visible only to their creators during the same connection to an instance of SQL Server as when the tables were first created or referenced. Local temporary tables are deleted after the user disconnects from the instance of SQL Server. Global temporary tables are visible to any user and any connection after they are created, and are deleted when all users that are referencing the table disconnect from the instance of SQL Server. Tables are visible only in the current session Tables are visible to all sessions. Cannot be shared between multiple users. Can be shared between multiple users. Example Local Temporary table SELECT * FROM #temp Global Temporary table SELECT * FROM ##temp  

The ASP.NET page framework also supports an automatic way to associate page events and methods. If the AutoEventWireup attribute of the Page directive is set to true (or if it is missing, since by default it is true ),  AutoEventWireup is an attribute in Page directive.   AutoEventWireup is a Boolean attribute that indicates whether the ASP.NET pages events are auto-wired.  AutoEventWireup will have a value true or false . By default it is true . <% @ Page Language ="C#" AutoEventWireup ="true" CodeBehind ="Default.aspx.cs" Inherits ="WebApplication2._Default" %> the page framework calls page events automatically, specifically the Page_Init and Page_Load methods. In that case, no explicit Handles clause or delegate is needed. Example 1 With AutoEventWireup ="true" HTML Code <% @ Page Language ="C#" AutoEventWireup ="true" CodeBehind =&