If you need to query all People from Person table with FirstName start with A, you can easily query like below,
What if you want to list all the people from person table with first name start with A and B? You can combined Like operator with OR and query like below,
But imagine scenario where you need to query all the People with FirstName start with A to M. How will you do that?
Solution is you need to put like operator in the square bracket as below,
If you modify one little thing in above query and replace like operator with equal operator , you will get no error message however you will get no rows returned as well.
Have you ever thought, what if your table name
1. Is exactly as of SQL Server keyword
2. Is having space in between like Student Fav Actor
If you go ahead and query against table Student Fav Actor like below, most likely you will get error message as below,
There may me one more scenario where table name is something like FROM. If you query in usual way, obviously you will be getting expected error message.
So how to query table named [However this is wrong practice to put spaces and use SQL Server keyword as table name] like above?
Very simple is the solution, put table name in square brackets.
You might encounter columns name of table are having spaces or named as keywords. In that case also you need to apply square bracket with that particular column name to work with.
Level: Beginners [level 100]
Output clause gives access to Inserted, updated or deleted rows of table. In SQL Server 2005 this was possible only through Triggers.
Note: In all explanation, I am going to use School Database. You can download script from here
Imagine a scenario that while inserting a value in Person table, for the audit purpose you need to insert value FirstName column and insertion date in audit table. This was possible in SQL Server through Triggers. Whereas in SQL Server 2008 we can achieve this using Output clause
I created a table called Audit_Person in school database.
Now while inserting in Person table, I need to insert a row in this table also.
In above statement if you notice we are fetching inserted first name using Inserted.FirstName and current date using GetDate and inserting in Audit_Person table.
Let us say you have another scenario in which
- You want to delete all the person First Name started with P
- Insert First Name of deleted row with deleted date in Audit_Person table
To write above query you can use Output clause.
Scripts used in above explanation are below. Feel free to use them
Create table Audit_Person
Insert into Person(LastName ,FirstName)
Delete from Person
Output deleted.Firstname ,
where FirstName like 'P%';
I hope this post was useful. Thanks for reading