Archive
FW: Days Since Last Event: TSQL vs. MDX vs. DAX
There is a nice blog discussing “Days Since Last Event”, you can find it here.
It compares the same logic implemented by TSQL, MDX and DAX. In my perspective, the TSQL is the most easy to understand. The MDX (2nd solution) is elegant. The DAX one is the hardest to understand. (Tips: don’t read the DAX code in the text, read from the screenshot and the code is formatted better).
PowerPivot’s limitation to SSAS
PowerPivot for SharePoint Architecture video’s
The below page has several links to some videos taling about PowerPivot and SharePoint integration. Quite interesting and deep dive into the technology.
http://www.powerpivotblog.nl/powerpivot-for-sharepoint-architecture-videos
Avoid using FILTER on entire table in PowerPivot DAX
Kasper de Jonge has a nice blog item (http://www.powerpivotblog.nl/tune-your-powerpivot-dax-query-dont-use-the-entire-table-in-a-filter-and-replace-sumx-if-possible) showing that using FILTER function on an entite table has performance issue. As FILTER will create a copy of the entire table in the memory, it is a very expensive function in DAX.
Using VALUEs(<Column>) if you are going to filter based on an indivudual column. Rather than FILTER, VALUES creates a one-column table which doesn’t contain duplicated value (think it as Distinct in T-SQL).
