SQL DELETE Statement

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In this step by step SQL Tutorial I will show you how to remove rows from a table . For the purpose of this tutorial I will use SQL Server 2012.

 

Other Versions of SQL Server:

  • SQL Server 2012
    • This blog post has been written using SQL Server 2012
  • SQL Server 2008 / R2
    • The examples we used should work in SQL Server 2008 and R2
  • SQL Server 2005
    • We suspect that this will work in SQL Server 2005 as well

 

Who is it for?

  • People who would like to learn basics of using SQL DELETE 
  • Those who are preparing for Microsoft certifications and need to cover this topic.

 

Content:

 

DELETE Introduction

Delete allows to remove rows from a table and you can write delete query with filters so you delete only the rows you want.

To better understand DELETE let's create a task that is close to real-life. In our story imagine you are a developer
that has been ask to clean your table before loading new data from spreadsheet. In the  following example I will show you how you could solve your task.

 

DELETE using SSMS 2012

 

For this example I will use AdventureWorksDW2012 database, dbo.DatabaseLog table. 

 

I retrieve all data (*) From dbo.DatabaseLog and check how many rows I have got now. 

 

I use DELETE statement to remove all records from dbo.DatabaseLog. You can see that in the Messages window under my script is message saying that 112 rows was deleted.

 

Now I just check if my table is empty and you can see that all columns contain not data.

 

DELETE with WHERE Statement

In the Object Explorer I go to AdventureWorksDW2012, dbo.DimCusomer.

 

I open the table and find CustomerKey for row Katie Glownia.

 

I check rows number for DimCusomer table 

 

I type script to delete customer key 29485 and run my query 

 

I get Message saing that 1 row was deleted sucessfully.

 

I can see that in the DimCustomer last row containg data about Katie Glownia is not existing.

I have 18484 rows in DimCustemer.

 

I hope that will help you 

Katie 


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Name: ken
Date Posted: 9/6/2012 10:35:25 AM
Comment:

i am happy with ur work. pls help to get sql server 2012.






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