Create queries, functions, and parameters by using the Power Query Advanced Editor

The Power Query Advanced Editor is a powerful tool that allows users to create complex queries, functions, and parameters in Microsoft Power BI. This feature is particularly useful for designing and implementing enterprise-scale analytics solutions using Microsoft Azure and Power BI. In this article, we will explore how to utilize the Advanced Editor to enhance your data transformation and integration processes.

Creating Queries

To create a new query using the Advanced Editor, start by defining the data source. This can be done by specifying the source type (e.g., Excel, SQL Server, Azure Blob Storage) and providing the necessary connection details. Here’s an example of creating a query that retrieves data from an Excel file:

let
source = Excel.Workbook(File.Contents("C:\Data\Sample.xlsx"), null, true),
sheet = source{[Item="Sheet1",Kind="Sheet"]}[Data],
table = sheet{[Item="Table1",Kind="Table"]}[Data]
in
table

In this example, the query retrieves data from Sheet1 and Table1 in the Sample.xlsx file located at “C:\Data\”.

Modifying Queries

You can modify existing queries by editing the M code in the Advanced Editor. This gives you the flexibility to apply custom transformations to suit your specific requirements. For instance, you can filter data, rename columns, create calculated columns, or merge multiple queries. Here’s an example of adding a filter to a query:

let
source = Sql.Database("server_name", "database_name"),
salesTable = source{[Schema="dbo",Item="Sales"]}[Data],
filteredSales = Table.SelectRows(salesTable, each [Quantity] > 10)
in
filteredSales

In this example, the query filters the Sales table to only include rows where the Quantity is greater than 10.

Defining Functions and Parameters

Functions and parameters in Power Query can be used to encapsulate reusable logic and make your queries more dynamic. You can define functions to perform specific operations and parameters to pass values to these functions. Here’s an example of defining a function that calculates the total price of an item given the quantity and unit price:

let
calculateTotalPrice = (quantity, unitPrice) => quantity * unitPrice,
totalPrice = calculateTotalPrice(5, 10)
in
totalPrice

In this example, the function “calculateTotalPrice” multiplies the quantity and unit price to get the total price. The “totalPrice” variable then calls the function with values 5 and 10.

With the Advanced Editor, you can utilize these functions and parameters to enhance your data transformation processes. For instance, you can pass parameters to filter data dynamically or define complex calculations. Here’s an example of using a parameter to filter data:

let
source = Excel.Workbook(File.Contents("C:\Data\Sample.xlsx"), null, true),
sheet = source{[Item="Sheet1",Kind="Sheet"]}[Data],
table = sheet{[Item="Table1",Kind="Table"]}[Data],
filteredTable = Table.SelectRows(table, each [Quantity] > QuantityThreshold),
QuantityThreshold = 10
in
filteredTable

In this example, the parameter “QuantityThreshold” is used to filter the Table1 based on the specified threshold.

In conclusion, the Power Query Advanced Editor is a powerful tool in Power BI that enables you to create queries, functions, and parameters for designing and implementing enterprise-scale analytics solutions. By leveraging this feature, you can have fine-grained control over the data transformation process, create reusable logic, and make your solutions more dynamic and flexible.