Power BI February 2022 Updates Dynamic M Query Parameters

Now supports SQL Server and more data sources

But what are Dynamic M Query Parameters and what does this mean?

It feels like they have been upgraded to use with direct query data sources so you can restrict the amount of data being asked for at the lowest level.

Lets have a look at a simple example using Taxi data from a Microsoft learning path.

First of all you need to open Power BI – Options and Settings – Options

Its in Preview so make sure that is ticked before continuing

Get Data Azure SQL Database (The guidance mentions SQL Server but it seems that both can be used for this test)

Load

Then go to Transform data.

Right Click on trip fares to get to advanced editor

let    
Source = Sql.Database("dataengineering-sqlserv.database.windows.net", "taxi-data-db"),    dbo_TripFares = Source{[Schema="dbo",Item="TripFares"]}[Data]
in   
 dbo_TripFares

Its currently bound to a table but we need to bind it to a query for this process.

Click the cog against source.

Go into Advanced Options and add the SQL Statement

SELECT * FROM dbo.TripFares

And then go back and look at advanced editor

let   
Source = Sql.Database("dataengineering-sqlserv.database.windows.net", "taxi-data-db", [Query="SELECT * FROM dbo.TripFares"]),    
dbo_TripFares = Source{[Schema="dbo",Item="TripFares"]}[Data]
in    
dbo_TripFares

So now, its nearly bound to a query but you will note that it looks like the table is erroring.

You can go back to Advanced Editor and change to

let
Source = Sql.Database("dataengineering-sqlserv.database.windows.net", "taxi-data-db", 
[Query="SELECT * FROM dbo.TripFares"])in   
 Source

 We only need the query and not dbo_TripFares

Now we can add the  Dynamic M Query parameters. I will go for an easy one first as a demo.

And then I change the advanced code again

let 
Source = Sql.Database("dataengineering-sqlserv.database.windows.net", "taxi-data-db", [Query="SELECT * FROM dbo.TripFares Where payment_type = '" & paramPaymentType & "'"])
in    
#"Source"

Note the new WHERE Clause that concatenates the value in our parameter

It will read in SQL SELECT * FROM dbo.TripFares Where payment_type = ‘CRD’

When it runs the first time you are asked to approve and you can actually see the SQL its going to use which is good. (Note I had to change to CSH to get the message up but I am running with CRD)

When it comes through its restricting to the selected payment type

We are going to change the code again

let    
filterQueryPaymentType = "SELECT * FROM dbo.TripFares Where payment_type = '" & paramPaymentType & "'",    
Source = Sql.Database("dataengineering-sqlserv.database.windows.net", "taxi-data-db", 
[Query=filterQueryPaymentType])
in  
#"Source"

This sets the SQL command first and we pass the Filter query into the data source

Now we know that the query works. Lets use it in Power BI Reporting and Assign to table.

This will need a lookup table of all the payment types to work

I am going to simply create the reference table in M

let
Source = Sql.Database("dataengineering-sqlserv.database.windows.net", "taxi-data-db", 
[Query="SELECT DISTINCT payment_Type FROM dbo.TripFares"])
in    #"Source"

Close and Apply

Now bind the table to the parameter in Modelling tab

Click on Payment_Type column. Advanced. Bind to parameter

Click Continue

A multi select is not going to be used for this demo

I have added a quick table. the metrics have come through as strings and there will be lots of things you need to test in direct query mode but I will ignore for the time being.

I dragged in Payment type from the Payment Type lookup into a slicer.

Click the slicer and see your data change. every time you click the slicer a direct query will happen but only for the payment type selected, hopefully making things much quicker.

And there you go. You have set up a restricted direct query. This will help with any direct query reports you need to create based on real time data.

You are still hitting the SQL DB though a lot so this would need thinking out.

And remember, Direct query doesnt give you the full Power BI reporting suite so your reports may be more basic. And usually I like to work with Star schemas but here we have the extra complexity of lookup tables to work with the parameters.

I will be looking at a date time example soon hopefully. This is clearly an extremely important piece of the Direct query real time puzzle.

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