Re-2: VReport general idea

[Beatrix Willius]

In general a pivot is more like a cross product.

Let's say you have the usual sales data:

Product		Date 		Amount
Valentina	01.01.2009	100
MySQL		15.02.2009	200
Valentina	17.02.2009	150
MySQL		19.03.2009	300
Valentina	19.02.2009	100

Now you want to know what products you sold per month. You do a pivot

			January February	March
Valentina	100		250			0
mySQL		0		200			300

A very long time ago I learned to pivot with Excel. It offers a nice  
visual way to learn it. Access has a wizard, which then can create  
the SQL from the pivot. It's an important tool for doing reports.

On 26.02.2009, at 16:01, Thorsten Hohage wrote:

> On 2009-02-26, at 15:25, Fabian Eschrich wrote:
>> Beatrix or Ruslan, can you explain PIVOT to me?
>
>
> in general a PIVOT is known as a MATRIX operation. A MATRIX can you
> imagine as an excel sheet, or a table with rows and columns, in the
> simplest case even one row or one column, or ONE "cell" is a MATRIX.
>
> Using pivot now means to switch the elements over the top left to
> bottom right diagonal line - an element in row 3 column 2 will be come
> the element in row 2 column 3 ....

Pivot doesn't have anything to do with transposing your data.

Mit freundlichen Grüßen/Regards

Trixi Willius

http://www.mothsoftware.com
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