Re: Having a bad SQL day - Database Discussion Boards

To add to Jorgen's answer, I've always wondered why SQL Server doesn't allow us to use alias in WHERE and HAVING clauses. The answer to that lies in the logical order in which the query is processed. The WHERE and HAVING clauses are processed before the SELECT clause and the alias do not exist at that stage.

However, technically it should be possible to introduce another stage earlier in the query processing pipeline where a mapping between expressions and their alias is made and WHERE and HAVING clauses can look up to these mappings and substitute the actual expression in place of the alias.

You are looking for CTE. "The ones who care enough to do it right care too much to compromise." Matthew Faithfull
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Yes, or a simple SELECT ... FROM ( SELECT ... FROM table WHERE ... ) T ...
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Yes, thats equivalent. I just prefer the readability of the CTE (which is merely an opinion) plus that you can refer to a CTE in more than one place. "The ones who care enough to do it right care too much to compromise." Matthew Faithfull
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Ado.net is the Library in .net technology. this library help to you for connect your application to the database.

- Now Come in depth

C# is a language. and responsible to create the User Interface like Console, Web, and Window Application.

SQL is also language for create the database and database store the data.

Suppose i need to connect my Front-End to the Back-End.
or We say that C# Communicate to the SQL. now its not possible to two different language communicate to each other. Simple Example is
One Person is Russian and second is Indian now they want to talk to each other. Big Problem Occur when they want to communicate because Russian not known the Hindi language and similar Indian not know the Russian Language. now both person need to mediator or Converter. Converter convert the language means for Indian to Hindi and Russian to Russian Language.

-----Ado.Net Mediator between the Front-End to the Back-End-----
Ado.Net is provider to make the connection between the Front-End to the Back-End.

Thank you

Student of Dr. Sandeep Karan CAC Noida
Himanshu Sharma

And what is your question?
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That's not a question, it's a Tip (or atleast he thinks so)
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This is really a great tip for the beginners. i thank you from all the Beginners those who need a Elaborated definition to understand the concepts..
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If you seek more knowledge on how to talk to database from C# using ADO.NET, read: MSDN: ADO.NET[^] MSDN: Accessing Data with ADO.NET[^] Sandeep Mewara Microsoft ASP.NET MVP 2012 & 2013 [My Blog] [My Latest Post]: How to extend a WPF Textbox to Custom Picker
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What is the difference between truncating and deleting a table? After the truncating or deleting do we need to re-index or shrink the table? We are looking to do some clean-up on some rather large tables on our database. Once we do the clean-up what steps do we need to preform for overall database "health"? Thanks!
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