I have been the author of this book which was written for Syncfusion, to increase their offer on the Succinctly series. Two more books are on stack to be released so wait for more news in the following weeks.
PowerShell Succinctly highlights some of the PowerShell programming model’s many benefits, specifically for .NET developers and system administrators. Author Rui Machado guides readers through time-saving methods that simplify code testing by eliminating the need to create a new application in Visual Studio. Also included are tips for using additional services, such as PowerGui, WMI, and SQL Server, to get the most out of PowerShell. Even if you don’t already use scripting languages to manage your machines, PowerShell Succinctly will show you just how easy it is to automate activities, work with databases, and interact with a variety of file types with this useful model.
While querying our databases we might face a typical problema which is getting the next or the previous value of an atribute according to some rule applyed to a certain dataset. This happens more if you deal with datawarehouses and need to retrieve this kind of analytical information. The typical solutions involve several “group by” and sub queries to achieve the same result. This way SQL has a powerful feature which are the Analytical functions.
Analytic functions compute an aggregate value based on a group of rows. They differ from aggregate functions in that they return multiple rows for each group. The group of rows is called a window and is defined by the
analytic_clause. For each row, a sliding window of rows is defined. The window determines the range of rows used to perform the calculations for the current row. Window sizes can be based on either a physical number of rows or a logical interval such as time.