“Hi Pinal,

In SQL statement below the time difference between two given dates is 3 sec, but when checked in terms of Min it says 1 Min (whereas the actual min is 0.05Min)

SELECT DATEDIFF(MI,'2011-10-14 02:18:58' , '2011-10-14 02:19:01') AS MIN_DIFF

Is this is a BUG in SQL Server ?”

Answer is NO.

It is not a bug; it is a feature that works like that. Let us understand that in a bit more detail. When you instruct SQL Server to find the time difference in minutes, it just looks at the minute section only and completely ignores hour, second, millisecond, etc. So in terms of difference in minutes, it is indeed 1.

The following will also clear how DATEDIFF works:

SELECT DATEDIFF(YEAR,'2011-12-31 23:59:59' , '2012-01-01 00:00:00') AS YEAR_DIFF

The difference between the above dates is just 1 second, but in terms of year difference it shows 1.

If you want to have accuracy in seconds, you need to use a different approach. In the first example, the accurate method is to find the number of seconds first and then divide it by 60 to convert it to minutes.

SELECT DATEDIFF(second,'2011-10-14 02:18:58' , '2011-10-14 02:19:01')/60.0 AS MIN_DIFF

Even though the concept is very simple it is always a good idea to refresh it. Please share your related experience with me through your comments.

Reference: Pinal Dave (http://blog.SQLAuthority.com)

I have written over this subject earlier over here.

SQL SERVER – Difference Between GETDATE and SYSDATETIME

SQL SERVER – Difference Between DATETIME and DATETIME2 – WITH GETDATE

SQL SERVER – Difference Between DATETIME and DATETIME2

SQL Expert Jing Sheng Zhong has left following comment:

The issue you found in SQL server new datetime type is related time source function precision. Folks have found the root reason of the problem – when data time values are converted (implicit or explicit) between different data type, which would lose some precision, so the result cannot match each other as thought. Here I would like to gave a work around solution to solve the problem which the developers met.

-- Declare and loop
DECLARE @Intveral INT, @CurDate DATETIMEOFFSET;
CREATE TABLE #TimeTable (FirstDate DATETIME, LastDate DATETIME2, GlobalDate DATETIMEOFFSET)
SET @Intveral = 10000
WHILE (@Intveral > 0)
BEGIN
----SET @CurDate = SYSDATETIMEOFFSET(); -- higher precision for future use only
SET @CurDate = TODATETIMEOFFSET(GETDATE(),DATEDIFF(N,GETUTCDATE(),GETDATE())); -- lower precision to match exited date process
INSERT #TimeTable (FirstDate, LastDate, GlobalDate)
VALUES (@CurDate, @CurDate, @CurDate)
SET @Intveral = @Intveral - 1
END
GO
-- Distinct Values
SELECT COUNT(DISTINCT FirstDate) D_DATETIME,
COUNT(DISTINCT LastDate) D_DATETIME2,
COUNT(DISTINCT GlobalDate) D_SYSGETDATE
FROM #TimeTable
GO
-- Join
SELECT DISTINCT a.FirstDate,b.LastDate, b.GlobalDate, CAST(b.GlobalDate AS DATETIME) GlobalDateASDateTime
FROM #TimeTable a
INNER JOIN #TimeTable b ON a.FirstDate = CAST(b.GlobalDate AS DATETIME)
GO
-- Select
SELECT *
FROM #TimeTable
GO
-- Clean up
DROP TABLE #TimeTable
GO


If you read my blog SQL SERVER – Difference Between DATETIME and DATETIME2 you will notice that I have achieved the same using GETDATE().

Are you using DATETIME2 in your production environment? If yes, I am interested to know the use case.

Reference: Pinal Dave (http://www.SQLAuthority.com)

Let us go over the definition of the TODATETIMEOFFSET  from BOL: Returns a datetimeoffset value that is translated from a datetime2 expression.

What essentially it does is that changes the current offset only  offset which we defined. Let us see the example of the same.

SELECT SYSDATETIMEOFFSET() GetCurrentOffSet;
SELECT TODATETIMEOFFSET(SYSDATETIMEOFFSET(), '-04:00') 'GetCurrentOffSet-4';
SELECT TODATETIMEOFFSET(SYSDATETIMEOFFSET(), '-02:00') 'GetCurrentOffSet-2';
SELECT TODATETIMEOFFSET(SYSDATETIMEOFFSET(), '+00:00') 'GetCurrentOffSet+0';
SELECT TODATETIMEOFFSET(SYSDATETIMEOFFSET(), '+02:00') 'GetCurrentOffSet+2';
SELECT TODATETIMEOFFSET(SYSDATETIMEOFFSET(), '+04:00') 'GetCurrentOffSet+4';

Let us see the resultset below.

It is quite clear from the example that only offset changes in the time but unlike SWITCHOFFSET the datetime remains the same.

Reference : Pinal Dave (http://blog.SQLAuthority.com)

Here is quick definition of the same from BOL: Returns a datetimeoffset value that is changed from the stored time zone offset to a specified new time zone offset.

What essentially it does is that changes the current offset of the time to any other offset which we defined. Let us see the example of the same.

SELECT SYSDATETIMEOFFSET() GetCurrentOffSet;
SELECT SWITCHOFFSET(SYSDATETIMEOFFSET(), '-04:00') 'GetCurrentOffSet-4';
SELECT SWITCHOFFSET(SYSDATETIMEOFFSET(), '-02:00') 'GetCurrentOffSet-2';
SELECT SWITCHOFFSET(SYSDATETIMEOFFSET(), '+00:00') 'GetCurrentOffSet+0';
SELECT SWITCHOFFSET(SYSDATETIMEOFFSET(), '+02:00') 'GetCurrentOffSet+2';
SELECT SWITCHOFFSET(SYSDATETIMEOFFSET(), '+04:00') 'GetCurrentOffSet+4';

Now let us check the resultset of the same.

The example above clearly shows that Switch offset does not only change the offset; it also alters the current time. If you look at GetcurrentOffset, it is +5.30; but, you will notice that GetCurrentOffset-2 does not only change the offset to -2. It also changes the time with the appropriate time at Timezone -2.

I suggest that you run the code in SSMS Query Window and observe the code behavior.

Reference: Pinal Dave (http://blog.SQLAuthority.com)

I previously populated DATETIME and DATETIME2 field with SYSDATETIME, which gave me very different behavior as SYSDATETIME was rounded up/down for the DATETIME datatype. I just ran the same experiment but instead of populating SYSDATETIME in this script I will be using GETDATE function.
DECLARE @Intveral INT
SET @Intveral = 10000
CREATE TABLE #TimeTable (FirstDate DATETIME, LastDate DATETIME2)
WHILE (@Intveral > 0)
BEGIN
INSERT #TimeTable (FirstDate, LastDate)
VALUES (GETDATE(), GETDATE())
SET @Intveral = @Intveral - 1
END
GO
SELECT COUNT(DISTINCT FirstDate) D_FirstDate, COUNT(DISTINCT LastDate) D_LastDate
FROM #TimeTable
GO
SELECT DISTINCT a.FirstDate, b.LastDate
FROM #TimeTable a
INNER JOIN #TimeTable b ON a.FirstDate = b.LastDate
GO
SELECT *
FROM #TimeTable
GO
DROP TABLE #TimeTable
GO

Let us run above script and observe the results.

You will find that the values of GETDATE which is populated in both the columns FirstDate and LastDate are very much same. This is because GETDATE is of datatype DATETIME and the precision of the GETDATE is smaller than DATETIME2 there is no rounding happening.

In other word, this experiment is pointless. I have included this as I got 4 emails and 3 twitter questions on this subject. If your datatype of variable is smaller than column datatype there is no manipulation of data, if data type of variable is larger than column datatype the data is rounded.

Reference: Pinal Dave (http://www.SQLAuthority.com)

Filed under: Pinal Dave, SQL, SQL Authority, SQL DateTime, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology ]]> http://blog.sqlauthority.com/2010/06/12/sql-server-difference-between-datetime-and-datetime2-with-getdate/feed/ 7 pinaldave http://blog.sqlauthority.com/2010/06/11/sql-server-difference-between-datetime-and-datetime2/ http://blog.sqlauthority.com/2010/06/11/sql-server-difference-between-datetime-and-datetime2/#comments Fri, 11 Jun 2010 01:30:55 +0000 pinaldave http://blog.sqlauthority.com/?p=9217 ]]> Yesterday I have written a very quick blog post on SQL SERVER – Difference Between GETDATE and SYSDATETIME and I got tremendous response for the same. I suggest you read that blog post before continuing with this blog post today. I had asked people to honestly take part and share their view about the above two system functions.

There are few emails as well as few comments on the blog post asking a question on how did I come to know the difference between the same. The answer is from real world issues. I was called in for performance tuning consultancy, where I was asked a very strange question by one developer. Here is the situation faced by him.

System had a single table with two different columns of datetime. One column was datelastmodified and the second column was datefirstmodified. One of the columns was DATETIME and  the other was DATETIME2. Developer was populating each of them with SYSDATETIME. He assumed that the value inserted in the table will be the same. This table was only accessed by INSERT statement, and there were no updates done over it in application. One fine day, he ran distinct on both these columns and was surprised by the result. He always thought that both the tables will have the same data, but in fact, they had very different data.

He presented this scenario to me. I said this is not possible, but I had to agree with him when I looked at the resultset. Here is the simple script to demonstrate the problem he was facing. This is just a sample of the original table.

DECLARE @Intveral INT
SET @Intveral = 10000
CREATE TABLE #TimeTable (FirstDate DATETIME, LastDate DATETIME2)
WHILE (@Intveral > 0)
BEGIN
INSERT #TimeTable (FirstDate, LastDate)
VALUES (SYSDATETIME(), SYSDATETIME())
SET @Intveral = @Intveral - 1
END
GO
SELECT COUNT(DISTINCT FirstDate) D_GETDATE, COUNT(DISTINCT LastDate) D_SYSGETDATE
FROM #TimeTable
GO
SELECT DISTINCT a.FirstDate, b.LastDate
FROM #TimeTable a
INNER JOIN #TimeTable b ON a.FirstDate = b.LastDate
GO
SELECT *
FROM #TimeTable
GO
DROP TABLE #TimeTable
GO

Let us see the resultset.

You can clearly see from result that SYSDATETIME() does not populate the same value in both the fields. In fact, the value is either rounded down or rounded up in the field which is DATETIME. Eventhough we are populating the same value, the values are totally different in both the columns, thus resulting in the SELF JOIN fail and displaying of different DISTINCT values.

The best way is to use GETDATE() if you are using DATETIME, and SYSDATETIME() if you are using DATETIME2 to populate them with current date and time for accurately addressing the precision. As DATETIME2 is introduced in SQL Server 2008, the above script will only work with SQL Server 2008 and later versions.

I hope I have answered some of the questions asked yesterday.

Reference: Pinal Dave (http://www.SQLAuthority.com)

SELECT GETDATE() fn_GetDate, SYSDATETIME() fn_SysDateTime

In case of GETDATE the precision is till miliseconds and in case of SYSDATETIME the precision is till nanoseconds.

Now the questions is to you – did you know this? Be honest and please share your views. I already accepted that I did not know this in very first line.

This applies to SQL Server 2008 only.

Reference: Pinal Dave (http://www.SQLAuthority.com),

The precision of the datatype SMALLDATETIME is 1 minute. It discards the seconds by rounding up or rounding down any seconds greater than zero. Let us see the following example

DECLARE @varSDate AS SMALLDATETIME
SET @varSDate = '1900-01-01 12:12:01'
SELECT @varSDate C_SDT
SET @varSDate = '1900-01-01 12:12:29'
SELECT @varSDate C_SDT
SET @varSDate = '1900-01-01 12:12:30'
SELECT @varSDate C_SDT
SET @varSDate = '1900-01-01 12:12:59'
SELECT @varSDate C_SDT


Following is the result of the above script and note that any value between 0 (zero) and 59 is converted up or down.

The part that confuses the developers is the value of the seconds in the display. I think if it is not maintained or recorded, it should not be displayed as well.

Reference: Pinal Dave (http://blog.SQLAuthority.com)

DECLARE @varDate AS DATE
DECLARE @varTime AS TIME
SET @varDate = '10/10/2010'
SET @varTime = '12:12:12'
SELECT CAST(@varDate AS DATETIME) C_Date
SELECT CAST(@varTime AS DATETIME) C_Time


As seen in example when DATE is converted to DATETIME it adds the of midnight. When TIME is converted to DATETIME it adds the date of 1900 and it is something one wants to consider if you are going to run script from SQL Server 2008 to earlier version with CONVERT.

Reference: Pinal Dave (http://blog.SQLAuthority.com)

What I really liked about the script is that it is very easy to understand, and also it can be customized very quickly.

DECLARE @Year AS INT,
@FirstDateOfYear DATETIME,
@LastDateOfYear DATETIME
-- You can change @year to any year you desire
SELECT @year = 2010
SELECT @FirstDateOfYear = DATEADD(yyyy, @Year - 1900, 0)
SELECT @LastDateOfYear = DATEADD(yyyy, @Year - 1900 + 1, 0)
-- Creating Query to Prepare Year Data
;WITH cte AS (
SELECT 1 AS DayID,
@FirstDateOfYear AS FromDate,
DATENAME(dw, @FirstDateOfYear) AS Dayname
UNION ALL
SELECT cte.DayID + 1 AS DayID,
DATEADD(d, 1 ,cte.FromDate),
DATENAME(dw, DATEADD(d, 1 ,cte.FromDate)) AS Dayname
FROM cte
WHERE DATEADD(d,1,cte.FromDate) < @LastDateOfYear
)
SELECT FromDate AS Date, Dayname
FROM CTE
WHERE DayName IN ('Saturday','Sunday')
/*
WHERE DayName IN ('Saturday,Sunday') -- For Weekend
WHERE DayName NOT IN ('Saturday','Sunday') -- For Weekday
WHERE DayName LIKE 'Monday' -- For Monday
WHERE DayName LIKE 'Sunday' -- For Sunday
*/
OPTION (MaxRecursion 370)

The result will be dates along with days in next column as expected.

You are welcome to contribute any script, which you think can be helpful to others.

Reference: Pinal Dave (http://blog.SQLAuthority.com)

SQL Server 2000/2005

SELECT
CONVERT(VARCHAR(8),GETDATE(),108) AS HourMinuteSecond,
CONVERT(VARCHAR(8),GETDATE(),101) AS DateOnly
GO

SQL Server 2008

SELECT
CONVERT(TIME,GETDATE()) AS HourMinuteSecond,
CONVERT(DATE,GETDATE(),101) AS DateOnly
GO

I hope the above solution is clear to you all.

Reference : Pinal Dave (http://blog.SQLAuthority.com)

If a user wants to finds out when was the last table updated he can query dynamic management view (dmv) – sys.dm_db_index_usage_stats and easily figure out when was the table updated last. Let us comprehend this example by creating a table and updating it. We can use dmv to determine when it was updated last.

USE AdventureWorks
GO
CREATE TABLE Test
(ID INT,
COL VARCHAR(100))
GO
INSERT INTO Test
SELECT 1,'First'
UNION ALL
SELECT 2,'Second'
GO

Now we have created a table and populated it with data. Next, we will run the following query to find out when it was last updated.

SELECT OBJECT_NAME(OBJECT_ID) AS DatabaseName, last_user_update,*
FROM sys.dm_db_index_usage_stats
WHERE database_id = DB_ID( 'AdventureWorks')
AND OBJECT_ID=OBJECT_ID('test')

Running query provides accurate details of when was  the table last updated. If WHERE condition is entirely removed it will provide details of the entire database.

Reference : Pinal Dave (http://blog.sqlauthority.com)

Official explanation of WAITFOR clause from Book Online is “Blocks the execution of a batch, stored procedure, or transaction until a specified time or time interval is reached, or a specified statement modifies or returns at least one row.”

Option 1 : Waitfor Delay in executing T-SQL
T-SQL runs after particular delay is completed.

SELECT GETDATE() CurrentTime
WAITFOR DELAY '00:00:05' ---- 5 Second Delay
SELECT GETDATE() CurrentTime

Option 2 : Waitfor Time in executing T-SQL
T-SQL runs after particular time has arrived.

DECLARE @MyDateTime DATETIME
/* Add 5 seconds to current time so
system waits for 5 seconds*/
SET @MyDateTime = DATEADD(s,5,GETDATE())
SELECT GETDATE() CurrentTime
WAITFOR TIME @MyDateTime
SELECT GETDATE() CurrentTime

Reference : Pinal Dave (http://blog.SQLAuthority.com)

Method 1:
SELECT DATEADD(D, 0, DATEDIFF(D, 0, GETDATE()))

Method 2:
SELECT CONVERT(VARCHAR(10),GETDATE(),111)

I have summarized my post suggesting that either method works fine and I prefer to use Method 2. However, with additional tests and looking at SQL Server internals very carefully, I want to suggest that Method 1 is better in terms of performance. While running on GETDATE() both of the above functions are equally fast and efficient. However, when above query is ran on very large data table performance different is visible.

For testing purpose I have ran few queries where I am getting same result.

Run Following query 10 times with client statistics on ( Shift+Alter+S) in SSMS.

USE AdventureWorks
GO
SELECT DATEADD(d, 0, DATEDIFF(d, 0, StartDate))
FROM Production.WorkOrder
GO

Now run another query 10 times with client statistics on.

USE AdventureWorks
GO
SELECT CONVERT(VARCHAR(10),StartDate,111)
FROM Production.WorkOrder
GO

While looking at the average of statistics in it is clear that first query with DATEADD is much more efficient.

Let us compare both of the above script together and see the client statistics.

While comparing Numbers of Bytes sent across client and server as well client processing time, and total execution time in all case DATEADD is better. I suggest all my readers to use DATEADD when only DATEPART is required.

If you are using SQL Server 2008 it has new DATE datatype which does not have time part. I suggest to use DATE datatype or TIME datatype for users of SQL Server 2008. Read more SQL SERVER – 2008 – New DataTypes DATE and TIME.

If you want your date in any other format refer the UDF SQL SERVER – Get Date Time in Any Format – UDF – User Defined Functions.

Reference : Pinal Dave (http://blog.SQLAuthority.com)

Download SQL Server 2008 Interview Questions and Answers Complete List

UPDATE: This article series has been updated with new interview questions and answers series.

Interview is very important event for any person. A good interview leads to good career if candidate is willing to learn. I always enjoy interview questions and answers series. This is my very humble attempt to write SQL Server 2008 interview questions and answers. SQL Server is very large subject and not everything is usually asked in interview. In interview what matters the most is conceptual knowledge and learning attitude.

I have listed all the series in this post so that it can be easily downloaded and used. All the questions are collected and listed in one PDF which is here to download. If you have any question or if you want to add to any of the question please send me mail or write a comment.

SQL SERVER – 2008 – Interview Questions and Answers – Part 1

SQL SERVER – 2008 – Interview Questions and Answers – Part 2

SQL SERVER – 2008 – Interview Questions and Answers – Part 3

SQL SERVER – 2008 – Interview Questions and Answers – Part 4

SQL SERVER – 2008 – Interview Questions and Answers – Part 5

SQL SERVER – 2008 – Interview Questions and Answers – Part 6

SQL SERVER – 2008 – Interview Questions and Answers – Part 7

SQL SERVER – 2008 – Interview Questions and Answers – Part 8

Download SQL Server 2008 Interview Questions and Answers Complete List

Reference : Pinal Dave (http://blog.SQLAuthority.com)

SQL SERVER – 2008 – Interview Questions and Answers Complete List Download

3) Questions of SQL SERVER 2008

What are the basic functions for master, msdb, model, tempdb and resource databases?

The master database holds information for all databases located on the SQL Server instance and is theglue that holds the engine together. Because SQL Server cannot start without a functioning masterdatabase, you must administer this database with care.

The msdb database stores information regarding database backups, SQL Agent information, DTS packages, SQL Server jobs, and some replication information such as for log shipping.

The tempdb holds temporary objects such as global and local temporary tables and stored procedures.

The model is essentially a template database used in the creation of any new user database created in the instance.

The resoure Database is a read-only database that contains all the system objects that are included with SQL Server. SQL Server system objects, such as sys.objects, are physically persisted in the Resource database, but they logically appear in the sys schema of every database. The Resource database does not contain user data or user metadata.

What is Service Broker?

Service Broker is a message-queuing technology in SQL Server that allows developers to integrate SQL Server fully into distributed applications. Service Broker is feature which provides facility to SQL Server to send an asynchronous, transactional message. it allows a database to send a message to another database without waiting for the response, so the application will continue to function if the remote database is temporarily unavailable. (Read More Here)

Where SQL server user names and passwords are stored in SQL server?

They get stored in System Catalog Views sys.server_principals and sys.sql_logins.

What is Policy Management?

Policy Management in SQL SERVER 2008 allows you to define and enforce policies for configuring and managing SQL Server across the enterprise. Policy-Based Management is configured in SQL Server Management Studio (SSMS).  Navigate to the Object Explorer and expand the Management node and the Policy Management node; you will see the Policies, Conditions, and Facets nodes. (Read More Here)

What is Replication and Database Mirroring?

Database mirroring can be used with replication to provide availability for the publication database. Database mirroring involves two copies of a single database that typically reside on different computers. At any given time, only one copy of the database is currently available to clients which are known as the principal database. Updates made by clients to the principal database are applied on the other copy of the database, known as the mirror database. Mirroring involves applying the transaction log from every insertion, update, or deletion made on the principal database onto the mirror database.

What are Sparse Columns?

A sparse column is another tool used to reduce the amount of physical storage used in a database. They are the ordinary columns that have an optimized storage for null values. Sparse columns reduce the space requirements for null values at the cost of more overhead to retrieve nonnull values. (Read More Here)

What does TOP Operator Do?

The TOP operator is used to specify the number of rows to be returned by a query. The TOP operator has new addition in SQL SERVER 2008 that it accepts variables as well as literal values and can be used with INSERT, UPDATE, and DELETES statements.

What is CTE?

CTE is an abbreviation Common Table Expression. A Common Table Expression (CTE) is an expression that can be thought of as a temporary result set which is defined within the execution of a single SQL statement. A CTE is similar to a derived table in that it is not stored as an object and lasts only for the duration of the query. (Read More Here)

What is MERGE Statement?
MERGE is a new feature that provides an efficient way to perform multiple DML operations. In previous versions of SQL Server, we had to write separate statements to INSERT, UPDATE, or DELETE data based on certain conditions, but now, using MERGE statement we can include the logic of such data modifications in one statement that even checks when the data is matched then just update it and when unmatched then insert it. One of the most important advantages of MERGE statement is all the data is read and processed only once.  (Read More Here)

What is Filtered Index?

Filtered Index is used to index a portion of rows in a table that means it applies filter on INDEX which improves query performance, reduce index maintenance costs, and reduce index storage costs compared with full-table indexes. When we see an Index created with some where clause then that is actually a FILTERED INDEX.

Which are new data types introduced in SQL SERVER 2008?

The GEOMETRY Type: The GEOMETRY data type is a system .NET common language runtime (CLR) data type in SQL Server. This type represents data in a two-dimensional Euclidean coordinate system.

The GEOGRAPHY Type: The GEOGRAPHY datatype’s functions are the same as with GEOMETRY. The difference between the two is that when you specify GEOGRAPHY, you are usually specifying points in terms of latitude and longitude.

New Date and Time Datatypes: SQL Server 2008 introduces four new datatypes related to date and time: DATE, TIME, DATETIMEOFFSET, and DATETIME2.

• DATE: The new DATE type just stores the date itself. It is based on the Gregorian calendar and handles years from 1 to 9999.
• TIME: The new TIME (n) type stores time with a range of 00:00:00.0000000 through 23:59:59.9999999. The precision is allowed with this type. TIME supports seconds down to 100 nanoseconds. The n in TIME (n) defines this level of fractional second precision, from 0 to 7 digits of precision.

• The DATETIMEOFFSET Type: DATETIMEOFFSET (n) is the time-zone-aware version of a datetime datatype. The name will appear less odd when you consider what it really is: a date + a time + a time-zone offset. The offset is based on how far behind or ahead you are from Coordinated Universal Time (UTC) time.

• The DATETIME2 Type: It is an extension of the datetime type in earlier versions of SQL Server. This new datatype has a date range covering dates from January 1 of year 1 through December 31 of year 9999. This is a definite improvement over the 1753 lower boundary of the datetime datatype. DATETIME2 not only includes the larger date range, but also has a timestamp and the same fractional precision that TIME type provides

What are the Advantages of using CTE?

• Using CTE improves the readability and makes maintenance of complex queries easy.
• The query can be divided into separate, simple, logical building blocks which can be then used to build more complex CTEs until final result set is generated.
• CTE can be defined in functions, stored procedures, triggers or even views.
• After a CTE is defined, it can be used as a Table or a View and can SELECT, INSERT, UPDATE or DELETE Data.

© Copyright 2000-2009 Pinal Dave. All Rights Reserved. SQLAuthority.com

Reference : Pinal Dave (http://blog.SQLAuthority.com)

----Today
SELECT GETDATE() 'Today'
----Yesterday
SELECT DATEADD(d,-1,GETDATE()) 'Yesterday'
----First Day of Current Week
SELECT DATEADD(wk,DATEDIFF(wk,0,GETDATE()),0) 'First Day of Current Week'
----Last Day of Current Week
SELECT DATEADD(wk,DATEDIFF(wk,0,GETDATE()),6) 'Last Day of Current Week'
----First Day of Last Week
SELECT DATEADD(wk,DATEDIFF(wk,7,GETDATE()),0) 'First Day of Last Week'
----Last Day of Last Week
SELECT DATEADD(wk,DATEDIFF(wk,7,GETDATE()),6) 'Last Day of Last Week'
----First Day of Current Month
SELECT DATEADD(mm,DATEDIFF(mm,0,GETDATE()),0) 'First Day of Current Month'
----Last Day of Current Month
SELECT DATEADD(ms,- 3,DATEADD(mm,0,DATEADD(mm,DATEDIFF(mm,0,GETDATE())+1,0))) 'Last Day of Current Month'
----First Day of Last Month
SELECT DATEADD(mm,-1,DATEADD(mm,DATEDIFF(mm,0,GETDATE()),0)) 'First Day of Last Month'
----Last Day of Last Month
SELECT DATEADD(ms,-3,DATEADD(mm,0,DATEADD(mm,DATEDIFF(mm,0,GETDATE()),0))) 'Last Day of Last Month'
----First Day of Current Year
SELECT DATEADD(yy,DATEDIFF(yy,0,GETDATE()),0) 'First Day of Current Year'
----Last Day of Current Year
SELECT DATEADD(ms,-3,DATEADD(yy,0,DATEADD(yy,DATEDIFF(yy,0,GETDATE())+1,0))) 'Last Day of Current Year'
----First Day of Last Year
SELECT DATEADD(yy,-1,DATEADD(yy,DATEDIFF(yy,0,GETDATE()),0)) 'First Day of Last Year'
----Last Day of Last Year
SELECT DATEADD(ms,-3,DATEADD(yy,0,DATEADD(yy,DATEDIFF(yy,0,GETDATE()),0))) 'Last Day of Last Year'

ResultSet:

Today
———————–
2008-08-29 21:54:58.967

Yesterday
———————–
2008-08-28 21:54:58.967

First Day of Current Week
————————-
2008-08-25 00:00:00.000

Last Day of Current Week
————————
2008-08-31 00:00:00.000

First Day of Last Week
———————–
2008-08-18 00:00:00.000

Last Day of Last Week
———————–
2008-08-24 00:00:00.000

First Day of Current Month
————————–
2008-08-01 00:00:00.000

Last Day of Current Month
————————-
2008-08-31 23:59:59.997

First Day of Last Month
———————–
2008-07-01 00:00:00.000

Last Day of Last Month
———————–
2008-07-31 23:59:59.997

First Day of Current Year
————————-
2008-01-01 00:00:00.000

Last Day of Current Year
————————
2008-12-31 23:59:59.997

First Day of Last Year
———————–
2007-01-01 00:00:00.000

Last Day of Last Year
———————–
2007-12-31 23:59:59.997

Reference : Pinal Dave (http://blog.SQLAuthority.com), Vivek Jamwal

Refer the function and get familiar yourself with different format this function support. I have added few examples of how this function can be used at the end of the article. You can download whole code in ZIP format as well.

Download Get Date Time in Any Format Script (ZIP)

CREATE FUNCTION [dbo].[ufsFormat]
(
@Date datetime,
@fORMAT VARCHAR(80)
)
RETURNS NVARCHAR(80)
AS
BEGIN
DECLARE @Dateformat INT
DECLARE @ReturnedDate VARCHAR(80)
DECLARE @TwelveHourClock INT
DECLARE @Before INT
DECLARE @pos INT
DECLARE @Escape INT
-- (c) Pinal Dave http://www.SQLAuthority.com
SELECT @ReturnedDate='error! unrecognised format '+@format
SELECT @DateFormat=CASE @format
WHEN 'mmm dd yyyy hh:mm AM/PM' THEN 100
WHEN 'mm/dd/yy' THEN 1
WHEN 'mm/dd/yyyy' THEN 101
WHEN 'yy.mm.dd' THEN 2
WHEN 'dd/mm/yy' THEN 3
WHEN 'dd.mm.yy' THEN 4
WHEN 'dd-mm-yy' THEN 5
WHEN 'dd Mmm yy' THEN 6
WHEN 'Mmm dd, yy' THEN 7
WHEN 'hh:mm:ss' THEN 8
WHEN 'yyyy.mm.dd' THEN 102
WHEN 'dd/mm/yyyy' THEN 103
WHEN 'dd.mm.yyyy' THEN 104
WHEN 'dd-mm-yyyy' THEN 105
WHEN 'dd Mmm yyyy' THEN 106
WHEN 'Mmm dd, yyyy' THEN 107
WHEN 'Mmm dd yyyy hh:mm:ss:ms AM/PM' THEN 9
WHEN 'Mmm dd yyyy hh:mi:ss:mmm AM/PM' THEN 9
WHEN 'Mmm dd yy hh:mm:ss:ms AM/PM' THEN 109
WHEN 'mm-dd-yy' THEN 10
WHEN 'mm-dd-yyyy' THEN 110
WHEN 'yy/mm/dd' THEN 11
WHEN 'yyyy/mm/dd' THEN 111
WHEN 'yymmdd' THEN 12
WHEN 'yyyymmdd' THEN 112
WHEN 'dd Mmm yyyy hh:mm:ss:Ms' THEN 113
WHEN 'hh:mm:ss:Ms' THEN 14
WHEN 'yyyy-mm-dd hh:mm:ss' THEN 120
WHEN 'yyyy-mm-dd hh:mm:ss.Ms' THEN 121
WHEN 'yyyy-mm-ddThh:mm:ss.Ms' THEN 126
WHEN 'dd Mmm yyyy hh:mm:ss:ms AM/PM' THEN 130
WHEN 'dd/mm/yy hh:mm:ss:ms AM/PM' THEN 131
WHEN 'RFC822' THEN 2
WHEN 'dd Mmm yyyy hh:mm' THEN 4
ELSE 1 END
SELECT @ReturnedDate='error! unrecognised format ' +@format+CONVERT(VARCHAR(10),@DateFormat)
IF @DateFormat>=0
SELECT @ReturnedDate=CONVERT(VARCHAR(80),@Date,@DateFormat)
--check for favourite and custom formats that can be done quickly
ELSE IF @DateFormat=-2--then it is RFC822 format
SELECT @ReturnedDate=LEFT(DATENAME(dw, @Date),3) + ', ' + STUFF(CONVERT(NVARCHAR,@Date,113),21,4,' GMT')
ELSE IF @DateFormat=-4--then it is european day format with minutes
SELECT @ReturnedDate=CONVERT(CHAR(17),@Date,113)
ELSE
BEGIN
SELECT @Before=LEN(@format)
SELECT @Format=REPLACE(REPLACE(REPLACE( @Format,'AM/PM','#'),'AM','#'),'PM','#')
SELECT @TwelveHourClock=CASE WHEN @Before >LEN(@format) THEN 109 ELSE 113 END, @ReturnedDate=''
WHILE (1=1)--forever
BEGIN
SELECT @pos=PATINDEX('%[yqmidwhs:#]%',@format+' ')
IF @pos=0--no more date format strings
BEGIN
SELECT @ReturnedDate=@ReturnedDate+@format
BREAK
END
IF @pos>1--some stuff to pass through first
BEGIN
SELECT @escape=CHARINDEX ('\',@Format+'\') --is it a literal character that is escaped?
IF @escape<@pos BEGIN
SET @ReturnedDate=@ReturnedDate+SUBSTRING(@Format,1,@escape-1) +SUBSTRING(@format,@escape+1,1)
SET @format=RTRIM(SUBSTRING(@Format,@Escape+2,80))
CONTINUE
END
SET @ReturnedDate=@ReturnedDate+SUBSTRING(@Format,1,@pos-1)
SET @format=RTRIM(SUBSTRING(@Format,@pos,80))
END
SELECT @pos=PATINDEX('%[^yqmidwhs:#]%',@format+' ')--get the end
SELECT @ReturnedDate=@ReturnedDate+--'('+substring(@Format,1,@pos-1)+')'+
CASE SUBSTRING(@Format,1,@pos-1)
--Mmmths as 1--12
WHEN 'M' THEN CONVERT(VARCHAR(2),DATEPART(MONTH,@Date))
--Mmmths as 01--12
WHEN 'Mm' THEN CONVERT(CHAR(2),@Date,101)
--Mmmths as Jan--Dec
WHEN 'Mmm' THEN CONVERT(CHAR(3),DATENAME(MONTH,@Date))
--Mmmths as January--December
WHEN 'Mmmm' THEN DATENAME(MONTH,@Date)
--Mmmths as the first letter of the Mmmth
WHEN 'Mmmmm' THEN CONVERT(CHAR(1),DATENAME(MONTH,@Date))
--Days as 1--31
WHEN 'D' THEN CONVERT(VARCHAR(2),DATEPART(DAY,@Date))
--Days as 01--31
WHEN 'Dd' THEN CONVERT(CHAR(2),@date,103)
--Days as Sun--Sat
WHEN 'Ddd' THEN CONVERT(CHAR(3),DATENAME(weekday,@Date))
--Days as Sunday--Saturday
WHEN 'Dddd' THEN DATENAME(weekday,@Date)
--Years as 00--99
WHEN 'Yy' THEN CONVERT(CHAR(2),@Date,12)
--Years as 1900--9999
WHEN 'Yyyy' THEN DATENAME(YEAR,@Date)
WHEN 'hh:mm:ss' THEN SUBSTRING(CONVERT(CHAR(30),@date,@TwelveHourClock),13,8)
WHEN 'hh:mm:ss:ms' THEN SUBSTRING(CONVERT(CHAR(30),@date,@TwelveHourClock),13,12)
WHEN 'h:mm:ss' THEN SUBSTRING(CONVERT(CHAR(30),@date,@TwelveHourClock),13,8)
--tthe SQL Server BOL syntax, for compatibility
WHEN 'hh:mi:ss:mmm' THEN SUBSTRING(CONVERT(CHAR(30),@date,@TwelveHourClock),13,12)
WHEN 'h:mm:ss:ms' THEN SUBSTRING(CONVERT(CHAR(30),@date,@TwelveHourClock),13,12)
WHEN 'H:m:s' THEN SUBSTRING(REPLACE(':'+SUBSTRING(CONVERT(CHAR(30), @Date,@TwelveHourClock),13,8),':0',':'),2,30)
WHEN 'H:m:s:ms' THEN SUBSTRING(REPLACE(':'+SUBSTRING(CONVERT(CHAR(30), @Date,@TwelveHourClock),13,12),':0',':'),2,30)
--Hours as 00--23
WHEN 'hh' THEN REPLACE(SUBSTRING(CONVERT(CHAR(30), @Date,@TwelveHourClock),13,2),' ','0')
--Hours as 0--23
WHEN 'h' THEN LTRIM(SUBSTRING(CONVERT(CHAR(30), @Date,@TwelveHourClock),13,2))
--Minutes as 00--59
WHEN 'Mi' THEN DATENAME(minute,@date)
WHEN 'mm' THEN DATENAME(minute,@date)
WHEN 'm' THEN CONVERT(VARCHAR(2),DATEPART(minute,@date))
--Seconds as 0--59
WHEN 'ss' THEN DATENAME(second,@date)
--Seconds as 0--59
WHEN 'S' THEN CONVERT(VARCHAR(2),DATEPART(second,@date))
--AM/PM
WHEN 'ms' THEN DATENAME(millisecond,@date)
WHEN 'mmm' THEN DATENAME(millisecond,@date)
WHEN 'dy' THEN DATENAME(dy,@date)
WHEN 'qq' THEN DATENAME(qq,@date)
WHEN 'ww' THEN DATENAME(ww,@date)
WHEN '#' THEN REVERSE(SUBSTRING(REVERSE(CONVERT(CHAR(26), @date,109)),1,2))
ELSE
SUBSTRING(@Format,1,@pos-1)
END
SET @format=RTRIM(SUBSTRING(@Format,@pos,80))
END
END
RETURN @ReturnedDate
END
GO
SELECT [dbo].[ufsFormat] ('8/7/2008', 'mm/dd/yy')
GO
SELECT [dbo].[ufsFormat] ('8/7/2008', 'hh:mm:ss')
GO
SELECT [dbo].[ufsFormat] ('8/7/2008', 'mmm')
GO
SELECT [dbo].[ufsFormat] ('8/7/2008', 'Mmm dd yyyy hh:mm:ss:ms AM/PM')
GO
SELECT [dbo].[ufsFormat] ('8/7/2008', '#')
GO


Reference : Pinal Dave (http://blog.SQLAuthority.com) , Nanda

First thing which comes to many users is using following script.

SELECT GETDATE() AS CurrentDateTime

Above method is not the only method to retrieve the current system date time for SQL Server. SQL Server 2008 has many different function which provides current system date time in different format and little difference in details.

SELECT 'SYSDATETIME' AS FunctionName, SYSDATETIME() AS DateTimeFormat
UNION ALL
SELECT 'SYSDATETIMEOFFSET', SYSDATETIMEOFFSET()
UNION ALL
SELECT 'SYSUTCDATETIME', SYSUTCDATETIME()
UNION ALL
SELECT 'CURRENT_TIMESTAMP', CURRENT_TIMESTAMP
UNION ALL
SELECT 'GETDATE', GETDATE()
UNION ALL
SELECT 'GETUTCDATE', GETUTCDATE()

In SQL Server 2008, use any of the above function depending on your need.

Reference : Pinal Dave (http://blog.SQLAuthority.com)

SQL SERVER – Retrieve Current Date Time in SQL Server CURRENT_TIMESTAMP, GETDATE(), {fn NOW()}

This post is related to new feature available in SQL Server 2008. In SQL Server 2008 there is a function which provides current offset of the system from GMT time as well. Basically it shows the system datetime with offset. I think this can be useful in some of the instances where SQL Server are depending on the time offset.

SELECT SYSDATETIMEOFFSET() AS 'Windows System Time'
GO

Reference : Pinal Dave (http://blog.SQLAuthority.com)

Note : This will not work with SQL Server 2005 or earlier version. This works with SQL Server 2008 only.

SELECT sqlserver_start_time
FROM sys.dm_os_sys_info

ResultSet:
sqlserver_start_time
———————–
2008-06-27 20:51:53.317

Reference : Pinal Dave (http://blog.SQLAuthority.com)

SELECT DATENAME(dw, GETDATE())

Reference : Pinal Dave (http://blog.SQLAuthority.com)

CREATE FUNCTION dbo.udf_DayOfWeek(@dtDate DATETIME)
RETURNS VARCHAR(10)
AS
BEGIN
DECLARE @rtDayofWeek VARCHAR(10)
DECLARE @weekDay INT
----Here I have subtracted 7 For keeping Sunday as the First day like wise for Monday we need to subtract 2 and so on
SET @weekDay=((DATEPART(dw,@dtDate)+@@DATEFIRST-7)%7)
SELECT @rtDayofWeek = CASE @weekDay
WHEN 1 THEN 'Sunday'
WHEN 2 THEN 'Monday'
WHEN 3 THEN 'Tuesday'
WHEN 4 THEN 'Wednesday'
WHEN 5 THEN 'Thursday'
WHEN 6 THEN 'Friday'
WHEN 0 THEN 'Saturday'
END
RETURN (@rtDayofWeek)
END
GO
SELECT dbo.udf_dayofweek(GETDATE())

Reference : Pinal Dave (http://blog.SQLAuthority.com) , Nanda Kumar

Reference : Pinal Dave (http://blog.SQLAuthority.com), Mihir Popat

I also encourage my other readers to submit their articles to me, if I think your article will benefit other readers I will publish it here with your name. Do not send me article if it is not written by you.

Step 1 : Create UDF to display current week date and day – Weekly Calender.
USE AdventureWorks;
GO
CREATE FUNCTION dbo.DisplayCurrentWeekDays
(@today SMALLDATETIME)
RETURNS @WeekDateDay TABLE
(
Sunday SMALLDATETIME,
Monday SMALLDATETIME,
Tuesday SMALLDATETIME,
Wednesday SMALLDATETIME,
Thursday SMALLDATETIME,
Friday SMALLDATETIME,
Saturday SMALLDATETIME
)
AS
/*
Purpose: To return the weekly calendar for the week any date
By: Pinal Dave -- SQLAuthority.com
On: 6/8/2007
*/
BEGIN
DECLARE @day INT
SET @today = CAST(CONVERT(VARCHAR(10), @today, 101) AS SMALLDATETIME)
SET @day = DATEPART(dw, @today)
INSERT INTO @WeekDateDay (Sunday, Monday,
Tuesday, Wednesday, Thursday, Friday, Saturday)
SELECT DATEADD(dd, 1 - @day, @today) Sunday,
DATEADD(dd, 2 - @day, @today) Monday,
DATEADD(dd, 3 - @day, @today) Tuesday,
DATEADD(dd, 4 - @day, @today) Wednesday,
DATEADD(dd, 5 - @day, @today) Thursday,
DATEADD(dd, 6 - @day, @today) Friday,
DATEADD(dd, 7 - @day, @today) Saturday
RETURN
END
GO

Step 2 : Create UDF to display current month date and day – Monthly Calender
USE AdventureWorks;
GO
CREATE FUNCTION dbo.GetSQLcalendar(@WhatDate SMALLDATETIME)
RETURNS @WeekDateDay TABLE
(
Sunday SMALLDATETIME,
Monday SMALLDATETIME,
Tuesday SMALLDATETIME,
Wednesday SMALLDATETIME,
Thursday SMALLDATETIME,
Friday SMALLDATETIME,
Saturday SMALLDATETIME
)
AS
BEGIN
/*
Purpose: To return a calendar fOR whatever MONTH you want,
driven by the date you pick AS a variable.
By: Dan Golden
On: 2/20/2008
*/
DECLARE @FourWeeksAgo SMALLDATETIME
SET @FourWeeksAgo = DATEADD(d,-28,@WhatDate)
DECLARE @ThreeWeeksAgo SMALLDATETIME
SET @ThreeWeeksAgo = DATEADD(d,-21,@WhatDate)
DECLARE @TwoWeeksAgo SMALLDATETIME
SET @TwoWeeksAgo = DATEADD(d,-14,@WhatDate)
DECLARE @PreviousWeek SMALLDATETIME
SET @PreviousWeek = DATEADD(d,-7,@WhatDate)
DECLARE @ThisWeek SMALLDATETIME
SET @ThisWeek = (@WhatDate)
DECLARE @NextWeek SMALLDATETIME
SET @NextWeek = DATEADD(d,7,@WhatDate)
DECLARE @LastWeek SMALLDATETIME
SET @LastWeek = DATEADD(d,14,@WhatDate)
DECLARE @AfterLastWeek SMALLDATETIME
SET @AfterLastWeek = DATEADD(d,21,@WhatDate)
DECLARE @TwoAfterLastWeek SMALLDATETIME
SET @TwoAfterLastWeek = DATEADD(d,28,@WhatDate)
INSERT INTO @WeekDateDay (Sunday, Monday, Tuesday,
Wednesday, Thursday, Friday, Saturday)
SELECT *
FROM
(
SELECT CASE MONTH(calendar.Sunday)
WHEN MONTH(@WhatDate)
THEN calendar.Sunday
ELSE NULL END AS 'Sunday',
CASE MONTH(calendar.Monday)
WHEN MONTH(@WhatDate)
THEN calendar.Monday
ELSE NULL END AS 'Monday',
CASE MONTH(calendar.Tuesday)
WHEN MONTH(@WhatDate)
THEN calendar.Tuesday
ELSE NULL END AS 'Tuesday',
CASE MONTH(calendar.Wednesday)
WHEN MONTH(@WhatDate)
THEN calendar.Wednesday
ELSE NULL END AS 'Wednesday',
CASE MONTH(calendar.Thursday)
WHEN MONTH(@WhatDate)
THEN calendar.Thursday
ELSE NULL END AS 'Thursday',
CASE MONTH(calendar.Friday)
WHEN MONTH(@WhatDate)
THEN calendar.Friday
ELSE NULL END AS 'Friday',
CASE MONTH(calendar.Saturday)
WHEN MONTH(@WhatDate)
THEN calendar.Saturday
ELSE NULL END AS 'Saturday'
FROM
(
SELECT *
FROM dbo.DisplayCurrentWeekDays(@FourWeeksAgo)
UNION ALL
SELECT *
FROM dbo.DisplayCurrentWeekDays(@ThreeWeeksAgo)
UNION ALL
SELECT *
FROM dbo.DisplayCurrentWeekDays(@TwoWeeksAgo)
UNION ALL
SELECT *
FROM dbo.DisplayCurrentWeekDays(@PreviousWeek)
UNION ALL
SELECT *
FROM dbo.DisplayCurrentWeekDays(@ThisWeek)
UNION ALL
SELECT *
FROM dbo.DisplayCurrentWeekDays(@NextWeek)
UNION ALL
SELECT *
FROM dbo.DisplayCurrentWeekDays(@LastWeek)
UNION ALL
SELECT *
FROM dbo.DisplayCurrentWeekDays(@AfterLastWeek)
UNION ALL
SELECT *
FROM dbo.DisplayCurrentWeekDays(@TwoAfterLastWeek)
) calendar
) dates
WHERE dates.sunday IS NOT NULL
OR dates.monday IS NOT NULL
OR dates.tuesday IS NOT NULL
OR dates.wednesday IS NOT NULL
OR dates.thursday IS NOT NULL
OR dates.friday IS NOT NULL
OR dates.saturday IS NOT NULL
RETURN
END
GO

Step 3 : Use recently created UDF to get the current month ‘s calender. You can pass any date to this calender and it will return that month and years calender.
USE AdventureWorks;
GO
DECLARE @WhatDay SMALLDATETIME
SELECT @WhatDay = GETDATE(); -- you can also put here any date like 07/01/1990
SELECT ISNULL(CONVERT(NVARCHAR(20), Sunday, 101), '') AS 'Sunday',
ISNULL(CONVERT(NVARCHAR(20), Monday, 101), '') AS 'Monday',
ISNULL(CONVERT(NVARCHAR(20), Tuesday, 101), '') AS 'Tuesday',
ISNULL(CONVERT(NVARCHAR(20), Wednesday, 101), '') AS 'Wednesday',
ISNULL(CONVERT(NVARCHAR(20), Thursday, 101), '') AS 'Thursday',
ISNULL(CONVERT(NVARCHAR(20), Friday, 101), '') AS 'Friday',
ISNULL(CONVERT(NVARCHAR(20), Saturday, 101), '') AS 'Saturday'
FROM dbo.GetSQLcalendar(@WhatDay)
GO

Above query will return you monthly calender for date passed to function.

Reference : Pinal Dave (http://blog.SQLAuthority.com) , Dan Golden