Calculated Columns Vs Measures In Power BI
*Important Note*?- This is to brief you about Calculated Columns and Measures. These things could be a bit complex. So, if you find any trouble while working on this, do message me directly. Happy to help you??
?Difference Between Measure and Calculated Column
?Calculated Column
?Let’s understand how these are working one by one. Calculated Column is a column like any other columns, created in the table. However, the result of a calculated column is coming from calculating an expression (DAX). Usually, calculated column leverages a DAX expression that applies to every row in the dataset, and the result of that will be stored in the new column.
Example: Profit as a calculated column
Consider a table that we have sales and costs information in it.?Calculating Profit in such table would be simply deducting costs from sales for every row. So this basically would be a calculated column.
?DAX Expression:
?Profit =??FactInternetSales[SalesAmount] -??FactInternetSales[TotalProductCost]
Row by Row Calculation: Row Context
One of the very important concepts about the calculation that you apply in Calculated Column (In the majority of the cases, not always); is that the calculation in one row at a time, or in other words; row by row calculation. In below table; you can see the calculation result for every row stored into the new column.
This means that more calculated memory you have, more memory consumption you will end up with, and your refresh time will be longer as well. However, many calculations are very simple, so your refresh time might not be affected too much.
?Based on above explanations, here are highlights of a calculated column;
·????????Row by row calculation: Row Context (usually, not always)
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·????????Stored in the memory (consumes RAM)
·????????calculated at the time of refreshing the report (either scheduled basis, or manual)
?What is Measure?
A measure is usually a calculation that works on an aggregated level basis. This aggregation can be as simple as a sum of sales or can be a little bit more complex, such as calculating monthly average sales in a rolling 12 months period. Measures have dynamic nature, they affect on a subset of data from one or more table. Hence, the subset of data can be changed?through the filters applied in the Power BI Report, then the calculation will have to be evaluated dynamically. So Measures are not pre-calculated, they will be calculated on the fly when adding it in the report.
Example: Sum of Sales
Measures are usually aggregations. A very simple aggregation we can use as an example is a sum of sales.
Aggregation can be done with a number of functions in DAX, such as Sum, SumX, Average, Calculate, and heaps of other aggregation functions. Now, let’s answer the most important question:
How to see the Value of the Measure?
Measures are calculated on the fly. This is, in fact, one of the most conceptual differences between a?measure and calculated column. Okay, measure values are calculated on the fly, so how you can see the value?! The answer is by putting that into a report!
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