Three different ways to find blocking in SQL

SP_WHO2	It shows blocking by the presence of blkby column value.
Sysprocesses	select * from master..sysprocesses where blocked >0
Activity Monitor	Open Activity Monitor at any time by pressing CTRL+ALT A.

Difference between 3 types of Restoring modes.

S.No	With Recovery	With Norecovery	Standby\Readonly
1	Leave the database in online mode.	Leave the database in restoring mode.	Leave the database in  readonly mode.
2	No further restore is possible.	Further restore is possible.	Further restore is possible.
3	User can able to access	Users can’t.	Users can able to read the  databases.
4	Rollback the uncommitted transactions	Does not rollback the uncommitted transactions	It undoes uncommitted transactions , but saves the undo actions in a  standby file so that recovery effects  can be reverted.

Difference between database roles and server roles

S.No	Server Roles	Database Roles
1	It is defined at the server level.	It is defined at the database level.
2	It exists outside of user databases.	It exists in each database.
3	There are fixed server roles only.	User defined database roles available.
4	Bulkadmin,dbcreator,diskadmin, processadmin,securityadmin, serveradmin,setupadmin and sysadmin(8)	Db_accesadmin,db_backupoperator, db_datareader,db_datawriter, db_ddladmin,db_denydatareader, db_denydatawriter,db_owner and db_securityadmin(9)

Differences between SQL2000,SQL2005 and SQL2008.

S.No	SQL 2000	SQL2005	SQL2008
1	Query Analyzer and Enterprise Manager are separate.	Both are combined as SQL SERVER MANAGEMEN STUDIO.	Both are combined as SQL SERVER MANAGEMEN STUDIO.
2	No XML datatype is used.	XML datatype is introduced.	XML datatype is used.
3	65,535 databases can be created.	2(pow(20))-1 databases can be created.	2(pow(20))-1 databases can be created.
4	Nill	Exception handling	Exception handling
5	Nill	Varchar(Max) datatype	Varchar(Max) datatype
6	Nill	DDL Triggers	DDL Triggers
7	Nill	Database mirroring	Database mirroring
8	Nill	Row number function for paging use.	Row number function for paging use.
9	Nill	Table fragmentation	Table fragmentation
10	Nill	Full text search	Full text search
11	Nill	Bulk copy update	Bulk copy update
12	Nill	Can’t encrypt	Can encrypt entire database
13	Compression not possible	Can compress tables and indexes(introduced in 2005 SP2)	Can compress tables and indexes
14	Datetime is used for both date and time	Datetime is used for both date and time	Date and time are separately used for date and time datatype
15	Nill	Narchar(max) and varbinary(max) is used.	Narchar(max) and varbinary(max) is used.
16	Nill	Nill	Table datatype is introduced.
17	Nill	SSIS is used.	SSIS is used.
18	Nill	Nill	Central Management Server(CMS) is introduced.
19	Nill	Nill	Policy based management is available.