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Sachin Nandanwar, Author at SQL Server Blogs, Events, Webcasts, Videos, SQL Server learning & education Sachin Nandanwar, Author at SQL Server Blogs, Events, Webcasts, Videos, SQL Server learning & education



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So far Sachin Nandanwar has created 8 entries.

SQL Server: Is Replication Recovery Model dependent ?

There is a myth that for replication to work properly the databases always have to be in Full recovery mode. Well that is not at all true.

First let me give a short overview on how replication works.

A snapshot agent creates a snapshot of the Publisher which is then taken up by the Distributor agent […]

SQL Server Phantom Reads In Repeatable read ??? I dont think so….

According to BOL Repeatable transaction isolation level will give a repeated (consistent) view of the data for that particular resultset in a transaction.Here is the exact definition

“Specifies that statements cannot read data that has been modified but not yet committed by other transactions and that no other transactions can modify data that has been […]

Sparse Columns in SQL Server 2008

Prior to SQL Server 2008 there was a lot of space wastage due to the storage of the NULL bitmaps for tracking NULL values in columns defined as NULL.SQL reserves the same space for columns  as the data length irrespective of whether it contains NULL or NOT NULL values.For varied length columns it stores […]

SQL Multiply all values in a column


Most of you reading this blog must be aware that SQL Server has an aggregate function called SUM to add all the values in a column.But what if you want to multiply all the values in a column.

Well still no inbuilt function has been available as yet but one can use the following query […]

Ghost Records in SQL Server… Now whats that ????

I always wondered what happens when a row is deleted from a table.Does SQL server directly overwrites the record or makes it invalid or it does something which is undocumented.Little bit of googling let me to this http://blogs.msdn.com/b/sqlserverstorageengine/archive/2006/06/23/644607.aspx

There was brief description done by Paul Randal in the msdn blog quoted above.
“These are records that […]

By |April 10th, 2011|Categories: SQL Server|Tags: |0 Comments

SQL Server Index Range query

There is a myth going around that for columns which are used as predicates always should have a clustered index which is backed up  and recommended by  Micorsoft  http://technet.microsoft.com/en-us/library/ms190639. aspx

Let us see whether this  indeed is true.Let us create a table T with approximately a million records.

Create Table T(Id Int ,NM Char(20) DEFAULT ”)


Insert into […]

By |April 8th, 2011|Categories: SQL Server||0 Comments

SQL Server: Sum of values for Time Slots

I had a bit of an unusual task where I needed to find the sum of values in between specific time interval slot for dates.Below is a small sample of the data.Here I need to find the sum of values for slots of 5 minutes.This is what I came up with.

Sample Data and Query

Declare […]

By |April 5th, 2011|Categories: SQL Server||0 Comments

SQL Server: How does SQL Server treats NULL values ?

Definition of NULL values.Extract from BOL

A value of NULL indicates that the value is unknown. A value of NULL is different from an empty or zero value. No two null values are equal. Comparisons between two null values, or between a NULL and any other value, return unknown because the value of each NULL […]

By |April 2nd, 2011|Categories: SQL Server||0 Comments