NOTE: This post was written before Data Explorer was renamed as Power Query. All of the content is still relevant to Power Query.

Yes, I know, I’ve been blogging a lot over the last week or so – I can’t help it, there’s been so much interesting stuff to blog about! Anyway, here’s yet another post about Data Explorer; not about functionality this time, but the result of some investigations about how it works and some ideas that resulted from that.

After having played around with Data Explorer so much, I started to wonder just how scalable it is. In the course of doing this I found out that while Data Explorer can (and must) do a lot of the data processing logic itself, it pushes as much of that logic back to the data source whenever it can. For example, if you connect to the Adventure Works DW database in SQL Server and then implement some simple steps in a Data Explorer query that:

1. Import everything from the DimDate table, hiding everything except the DayNumberOfWeek column
2. Filter it so that DayNumberOfWeek is greater than 5:
   = Table.SelectRows(DimDate, each [DayNumberOfWeek] > 5)
3. Return the count of the number of rows that are returned:
   = Table.RowCount(FilteredRows)

…you can see if you run a Profiler trace that all of this logic is translated to SQL and not evaluated in Data Explorer itself. Here’s the final SQL statement generated by the third step above:

select count(1) as [$Item]
from
(
select [_].[DayNumberOfWeek]
from
(
select [DayNumberOfWeek]
from [dbo].[DimDate] as [$Table]
) as [_]
where [_].[DayNumberOfWeek] > 5
) as [$Table]

I’m not sure which other data sources this is possible for, but it’s a good thing to see – you’re more likely to get good performance by doing the work back in the database than on your desktop. I wonder if it does this for Hive queries? If so, that would make it very useful for working with Hadoop/HDInsight.

And what about data sources where this isn’t possible though, like csv? I decided to test it out by loading a very large (1.4 GB) csv file I have with two columns containing integer values and 86 million rows, filtering it so that one of the column values was not null and less than 500000, and finding the resulting count of rows. Unfortunately I had to kill the query refresh after 15 minutes… In contrast, loading the same file into the Excel Data Model took almost exactly 6 minutes, and a DAX measure to do the same count/filter operation returned instantly. Not really a surprise I suppose, but it would be nice to have the option when working with csv files to load data into the Excel Data Model before you did anything else and then, when you did your transforms in Data Explorer, have those translated back to DAX queries and calculations. Alas, Data Explorer doesn’t support the Excel Data Model, PowerPivot or SSAS as data sources at the moment – I hope this changes soon.

This leads me on to the observation that in a lot of self-service BI scenarios the distinction between ETL and reporting can be blurred. If you just want to see a simple table showing your sales broken down by product in an Excel spreadsheet, you could build this quite easily with Data Explorer and not go near PowerPivot or the Excel Data Model. It would probably be easier to build too, since Data Explorer allows you to break complex operations into multiple steps, whereas putting all your logic in a single DAX expression can be mind-bendingly difficult (I’m reminded of this post I wrote two years ago). On the other hand you can do a lot of ETL-type things inside PowerPivot with calculated columns and measures; people have also been asking for the ability to use tables in the Excel Data Model as a data source for other tables (see here for example), for ETL purposes – it can be much faster and more elegant to use DAX to do some types of ETL work than SQL or SSIS. In the future I’d love to see tighter integration between Data Explorer and the Excel Data Model/PowerPivot so that we can get the best of both worlds.

NOTE: This post was written before Data Explorer was renamed as Power Query. All of the content is still relevant to Power Query.

Don’t you hate it when you get ready to blog about something cool, and then someone comes along and beats you to it? That’s what’s just happened to me – Matt Masson just wrote an excellent blog post on how to do address lookup against a web service here:
http://www.mattmasson.com/2013/03/dynamic-lookups-with-data-explorer/
That’s what I was going to write about in part 2 of this series. I have to say he did a better job than I would have done though, and shows off several cool tricks I hadn’t seen before…

Ah well, so it goes – and anyway there are a few things I was going to say that are still worth saying. If you remember, in Part 1 I showed how to call the Google Distance Matrix API from Data Explorer, but I hard-coded the start and end points in the expression I used. How can you get the start and end points directly from Excel? Well it turns out that Data Explorer can read values direct from Excel tables.

To start with, you need to create some Excel tables to hold the values you want to use. I created two Excel tables called Origin and Destination to hold the two values I needed:

I can then take the value from the first row in the sole column of each table (which are again called Origin and Destination, as you can see) by using

Excel.CurrentWorkbook(){[Name=”Origin”]}[Content]{0}[Origin]

and

Excel.CurrentWorkbook(){[Name=”Destination”]}[Content]{0}[Destination]

Here’s the full source expression with the hard-coded values replaced:

=
Xml.Document(
Web.Contents(
“http://maps.googleapis.com/maps/api/distancematrix/xml”
, [Query = [
origins= Excel.CurrentWorkbook(){[Name=”Origin”]}[Content]{0}[Origin]
, destinations = Excel.CurrentWorkbook(){[Name=”Destination”]}[Content]{0}[Destination]
, mode = “driving”, sensor = “false” ] ]))

Now, you can enter any address in the Origin and Destination tables, click Refresh on the Query as shown in the screenshot below:

And the query will be rerun with the new parameters. Note that it might also be a good idea to URL encode any text that you enter in these tables, using the EncodeURL() Excel function; I haven’t done so here because I’m using UK postcodes, which don’t need URL encoding, as my origins and destinations to make things simple.

It’s also possible to use the results of one query inside another query. Data Explorer allows you to use an Excel table as the source for a query:

And selecting the Destination Excel table as a source gives the following expression:

= Excel.CurrentWorkbook(){[Name=”Destination”]}[Content]

The easy way to use any value from an existing query as the starting point for a new query is to right-click on a cell and select Add As New Query:

Doing this creates a new query with the value you clicked on a source:

Here’s the expression for the only step in the newly-created query:

= Destination{0}[Destination]

Even if this new query isn’t any use on its own, the expression shown here can be used in other queries. Here’s the original web service call adapted to use two other queries as its source:

= Xml.Document(
Web.Contents(
“http://maps.googleapis.com/maps/api/distancematrix/xml”
, [Query = [
origins= Origin{0}[Origin]
, destinations = Destination{0}[Destination]
, mode = “driving”, sensor = “false” ] ]))

However, as Matt shows in his post, this only works if Fast Combine is enabled, otherwise you’ll see an error message.

You can download the sample workbook for this post here.

NOTE: This post was written before Data Explorer was renamed as Power Query. All of the content is still relevant to Power Query.

Last week I showed how you could use the WebService() function in Excel 2013 to bring location data into Excel 2013. Since this is a topic I have a particular interest in, this week I’ll show you how to do the same thing all over again but in Data Explorer.

First of all, a simple example. In that previous post I used the Google Distance Matrix API to calculate the distance between two points; for example the following call shows how long it would take me to drive from my home to Buckingham Palace to see the Queen (52 minutes in case you’re wondering):
http://maps.googleapis.com/maps/api/distancematrix/xml?origins=HP66HF&destinations=SW1A1AA&mode=driving&sensor=false

The following post on the Data Explorer forum from James Terwilliger gives some helpful tips on how to consume web services from within Data Explorer:
http://social.msdn.microsoft.com/Forums/en-US/dataexplorer/thread/069b50e3-ab9e-4ee4-99a9-23440fcfc768

…but it’s not altogether straightforward. For example if you paste the link above into the From Web data source, you do get something returned but it’s extremely hard to find any useful data. Instead, I found the following steps worked:

• First, hit From Web and enter something in the URL box:
  
• This gives you a new web query, but you want to discard any auto-generated code in the first step. Instead, paste the following expression:= Xml.Document(
  Web.Contents(“http://maps.googleapis.com/maps/api/distancematrix/xml”
  , [Query = [ origins= “HP66HF”, destinations = “SW1A1AA”, mode = “driving”, sensor = “false” ] ]))

  

  This uses Web.Contents() to call the web service (as described in that forums reply) with the appropriate parameters. Xml.Document() is then used to interpret the response as an XML document.

• With this done, it’s quite easy to navigate through the XML by clicking on the Table links in each step to find the useful data:
  
• And finally hit Done to surface it the worksheet:
  

Some thoughts at this point: I don’t like the way the DE formula language is case-sensitive, and I suspect in the long run it will have to be either hidden or replaced with VBA or Excel formula language/DAX if it’s going to be used even by Excel power users. It is very, very powerful though, and luckily the UI is good enough to mean that 99% of users will never need to write DE formula language anyway.

The next question: I’ve hard-coded my origins and destinations in this example, but how can I read these values from the worksheet without my users having to open Data Explorer and edit the query? Tune in for Part 2 to find out!

NOTE: This post was written before Data Explorer was renamed as Power Query. All of the content is still relevant to Power Query.

It’s only been two days since the official Preview release of Data Explorer and already the blog posts about it are coming thick and fast. Here are some of the more interesting ones that I’ve seen that show what’s possible with it:
http://sqlblog.com/blogs/jamie_thomson/archive/2013/02/28/traversing-the-facebook-graph-using-data-explorer.aspx
http://www.mattmasson.com/index.php/2013/03/access-the-windows-azure-marketplace-from-data-explorer/
http://community.altiusconsulting.com/best-oscar-winning-film-my-first-data-explorer-adventure/
http://www.spsdemo.com/blog/Lists/Posts/Post.aspx?List=c67861cd-a0d9-4ed8-9d9d-9b29652a516f&ID=371&Web=f74569c2-ae3f-42c6-a3fa-9f099dfaeb7f

Obviously I can’t let everyone else have all the fun, so I thought I’d show how you can use Data Explorer to import data from multiple files, clean it, load it into a single table and then report on it.

First of all, the data. Like all bloggers I have an unhealthy interest in my blog stats, and one of the ways I monitor the hits on this site is using Statcounter. I’m also a bit of a miser, though, so I only use their freebie service and that means that I only get to see stats on the last 500 site visits. How can I analyse this data then? Well, Statcounter allow you to download log data as a csv file, so at about 2:30pm I downloaded one file and at 8:30pm I downloaded another.

Now, the first cool thing to show about Data Explorer is that you can import and merge data from multiple files with the same structure if they’re in the same folder. With both of my files in a folder called Blog Logs, and Excel open, the first thing you need to do is to the Data Explorer tab and hit From File/From Folder:

The next step is to enter the name of the folder with the files in in the dialog:

With that done, a new Query screen appears with a list of the files in the folder:

You then need to hit the icon with the two down arrows and a horizontal line that I’ve highlighted in the screenshot above, next to the Content heading. This then shows the data in the files (obviously I’ve had to scrub out the sensitive data here):

You can then use the first row as the column headers:

Filter the data so that the row with the second set of column headers is removed (I wonder if there’s a way to do this automatically when importing multiple csv files?) by clicking on the Date and Time column and deselecting the value “Date and Time” as shown:

Right-click on each column you don’t want to import (such as IP Address) and selecting Hide:

Right-click on the Date and Time column and select Remove Duplicates to remove any records that appear in both log files (I’m assuming that there were no cases where two people hit a page at exactly the same date and time, which of course may not be completely correct):

And force the Date and Time column to be treated as a Date/Time type:

And bingo, you’re done. Here are all the steps in the import, all of which can be edited, deleted, reordered etc:

The data is then loaded into a table in a worksheet (though you can turn that off), and by clicking “Load to data model” in the Query Settings pane you can load the data into the Excel data model:

(NB I found some issues with loading date data into the data model and US/European date formats that I’ve reported here, but don’t forget this is beta software so there are bound to be problems like this)

You can build cool Power View reports using this data:

Or even explore it on a 3D map with GeoFlow:

Fun, isn’t it?