Useful (Difficult) SQL Scripts

Here you will find a library of some very useful & difficult SQL scripts.

1. http://stackoverflow.com/questions/197369/library-of-useful-difficult-sql-scripts
This a StackOverFlow article which has some of the best links.  A must visit for all SQL guys...

http://wiki.lessthandot.com/index.php/Category:Microsoft_SQL_Server - This is by far the best site I have found for SQL Server scripts.
2. http://wiki.lessthandot.com/index.php/SQL_Server_Programming_Hacks_-_100%2B_List
3. http://wiki.lessthandot.com/index.php/SQL_Server_Admin_Hacks
4. http://vyaskn.tripod.com/code.htm
5. http://www.nigelrivett.net/
6. http://www.paragoncorporation.com/ArticleDetail.aspx?ArticleID=27
7. http://stackoverflow.com/questions/197111/fastest-get-duplicates-sql-script 
8. http://bit.ly/aHoHxD - Joe Celko's SQL puzzles & answers ebook


I will keep on adding links to this list & if anyone of you have some useful links then feel free to share it here by adding comments, you can even ask any Q's regarding SQL here.

So keep scripting....

How to get Sql server 2008 intellisense working for schema changes

The new feature "intellisense" added in sql server 2008 is making my life easier. And I am enjoying this feature a lot. But I noticed many times that when we make any changes to DB schema like creating / modifying database objects (tables, sprocs, ...) we don't notice the schema changes in intellisense in the same session. This made me too bad and many times I cursed Microsoft for this inclomplete feature. But after making some research on this, I have found the solution to get intellisense for new schema changes in current session.

Actually what happens when you connect to sql server 2008 using sql server management studio is, it queries for the current database schema and saves it somewhere. And It uses this schema information for showing the intellisense when the user is writing queries. But when we create/update the sql objects (sprocs, tables, views, ...) these won't be updated and the intellisense is pulled from old schema. That's why we don't notice the schema changes in intellisense unless we explicitly refresh the cache. In order to get new chema changes we must clear the intellisense cache.

To clear the intellisense cache we need to click Edit -> Intellisense -> RefreshLocalCache in sql server 2008 management studio as shown in below screen.

Sql Server 2008 Feature – Part1

Sql Server 2008 Key Features:
 
1) Initializing variable when you declare
declare @val as int =0
declare @currentdate as datetime = getdate()
print @val
print @currentdate

2) Compound assignment operators
–operator like +=,-=,/=,*/,%=
declare @val as int = 0
set @val += 10;
print @val
3) Add multiple row in single Insert Statement

CREATE TABLE Employee
(
EmpId int,
EmpCode varchar(50),
EmpName varchar(50)
);

INSERT INTO Employee(EmpId, EmpCode,EmpName)
  VALUES
  (1, 'emp1','emp1'),
  (2, 'emp1','emp1'),
  (3, 'emp1','emp1');

select * from Employee

4) New Data Types

Data Type	Data Type Use
Date	The Date property returns a Date data type.
Time	Returns values for any valid time of day between 00:00:00 and 23:59:59:9999999. It has a length of at least 8 positions and contains the time in hours,minutes, seconds and fractional seconds.
DateTime2	DateTime2 is an extension of the existing DATETIME type. It has a large date range and large default fractional precision. It has a length of at least 19 positions.
DateTimeOffSet	Returns values for year, month, day, valid time of day between 00:00:00 and 23:59:59:9999999 and offset, in hours, from UTC. It has a length of at least 25 positions.
Hierarchyid	The HierarchyId property is used to identify a position in a hierarchy.
Geography	The SQL Server geography data type stores ellipsoidal (round-earth) data, such as GPS latitude and longitude coordinates
Geometry	The Geometry property contains spatial data that represents information about the physical location and shape of geometric objects.

HierarchyId Data Type

   1: --Create Table Employee

   2: CREATE TABLE Employee

   3: (

   4: EmpId int,

   5: EmpBossId HIERARCHYID,

   6: --GetLevel --> returns the level of the current node in the hierarchy

   7: EmpLevel as EmpBossId.GetLevel() PERSISTED,

   8: EmpCode varchar(50),

   9: EmpName varchar(50)

  10: );

  11: Go

  12: -- Create Insert Store Procedure

  13: Alter PROCEDURE Employee_isp

  14:     @empid int,

  15:     @empbossid int,

  16:     @empcode varchar(50),

  17:     @empname varchar(50)

  18: AS

  19: BEGIN

  20: declare @hid HIERARCHYID,@empboss_hid HIERARCHYID,@last_hid HIERARCHYID

  21:  

  22: if @empbossid = 0 

  23: begin

  24:     set @hid = HIERARCHYID::GetRoot();

  25: end 

  26: else 

  27: begin

  28:   

  29:   SET @empboss_hid = (SELECT EmpBossId FROM Employee  WHERE empid = @empbossid);

  30:   SET @last_hid = (SELECT MAX(EmpBossId) FROM Employee WHERE EmpBossId.GetAncestor(1)= @empboss_hid);

  31:   SET @hid = @empboss_hid.GetDescendant(@last_hid, NULL);

  32: end

  33: INSERT INTO Employee(empid, EmpBossId, EmpCode, EmpName)

  34:             VALUES(@empid, @hid, @empcode, @empname);

  35: END

  36: GO

  37: --insert data

  38: --                     A1

  39: --                AL1           AR1

  40: --           AL1L     AL1R  AR1L   AR1R  

  41: --

  42: --

  43: EXEC Employee_isp @empid =  1, @empbossid = 0, @empcode = 'A1' ,@empname = 'A1';

  44: EXEC Employee_isp @empid =  2, @empbossid = 1, @empcode = 'AL1' ,@empname = 'AL1';

  45: EXEC Employee_isp @empid =  3, @empbossid = 1, @empcode = 'AR1' ,@empname = 'AR1';

  46: EXEC Employee_isp @empid =  4, @empbossid = 2, @empcode = 'AL1L' ,@empname = 'AL1L';

  47: EXEC Employee_isp @empid =  5, @empbossid = 2, @empcode = 'AL1R' ,@empname = 'AL1R';

  48: EXEC Employee_isp @empid =  6, @empbossid = 3, @empcode = 'AR1L' ,@empname = 'AR1L';

  49: EXEC Employee_isp @empid =  7, @empbossid = 3, @empcode = 'AR1R' ,@empname = 'AR1R';

Inserted Data Into Table 

Different Selection Criteria :

1) Find Employee As Per their Level means Grade 

   select * from Employee where Emplevel = 2

2) Get Child Node 

   SELECT Child.empid, Child.empname FROM Employee AS Parent JOIN Employee AS Child
          ON Parent.empid = 2 AND child.empbossid.IsDescendantOf(Parent.empbossid) = 1;

3) Get Parent Node

SELECT parent.empid, parent.empname
  FROM Employee AS Parent JOIN Employee AS Child
    ON child.empid = 4 AND child.empbossid.IsDescendantOf(Parent.empbossid) = 1;

more on HierarchyId Data Types refer:

http://amitpatriwala.wordpress.com/2009/10/23/hierarchyid-data-type/

5) Introduced New Functions

Function Name	Function Use
SYSDATETIME	Returns current date and time as DateTime2 value.
SYSUTCDATETIME	Returns current date and time in UTC as DateTime2 value
SYSDATETIMEOFFSET	Returns current date and time along with the system time zone as a DATETIMEOFFSET value
SWITCHOFFSET	Adjusts an input DATETIMEOFFSET value to a specified time zone, while preserving the UTC value. For example, the following code adjusts the current system datetimeoffset value to time zone GMT +05:00: SELECT SWITCHOFFSET(SYSDATETIMEOFFSET(), ‘-05:00′);
TODATETIMEOFFSET	sets the time zone offset of an input date and time value

6) Support Large User Define Types [UDT]

Sql Server 2008 supports large UDT,large UDTs can now reach up to 2 GB in size.

Reference Sites: 

http://technet.microsoft.com/en-us/library/cc721270.aspx