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Window Functions in SQL Server

When SQL Server introduced Window Functions in SQL Server 2005, it was done in a rather tentative way, with only a handful of functions being introduced. This was frustrating, as they remove the last excuse for cursor-based operations by providing aggregations over a partition of the result set, and imposing an ordered sequence over a partition. Now, with SQL Server 2012, we are soon to enjoy a full range of Window Functions. They are going to make for some much simpler SQL queries.
16-Jul-2014
PostgreSQL: Documentation: 9.1: SELECT

SELECT : SELECT retrieves rows from zero or more tables. The general processing of SELECT is as follows:
16-Jul-2014
PostgreSQL: Documentation: 9.1: Window Functions

9.19. Window Functions : Window functions provide the ability to perform calculations across sets of rows that are related to the current query row. See Section 3.5 for an introduction to this feature.
16-Jul-2014
PostgreSQL: Documentation: 9.1: Window Functions

3.5. Window Functions : A window function performs a calculation across a set of table rows that are somehow related to the current row. This is comparable to the type of calculation that can be done with an aggregate function. But unlike regular aggregate functions, use of a window function does not cause rows to become grouped into a single output row ? the rows retain their separate identities. Behind the scenes, the window function is able to access more than just the current row of the query result.
16-Jul-2014
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