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.
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.
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