WITH common_table_expression (Transact-SQL)

Can someone explain what 'WITH common_table_expression' for Transact-SQL is and why/when would be a good time to use? I have read the explanation on MSDN, but it doesn't really make much sense to me.
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Faiga DiegelSr Database EngineerCommented:
CTEs acts like a temporary view or vitual table. It is very useful when writing recursive queries.

Ive been using these as reference for creating CTEs:


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They can be used as view structures or "table variable like" structures.  Here is an article I wrote recently on how they can be used to recursively find blocking processes on your server:


computerstreberAuthor Commented:
Those are both great response. Thank you so much.
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Microsoft SQL Server 2005

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