Difference between calculated column and measure in Power BI
A calculated column is a column that is added to a table in the data model, and the calculation is performed on each row of the table.
The result is stored in the column, and the calculation is performed only once when the data is loaded or refreshed.
Calculated columns are useful when you want to add a new column to the table that is derived from the values in other columns, and you want the result to be available for all further calculations.
A Measure is a calculation that is performed on the fly, based on the data in the columns of the table.
Measures are not stored in the table, but are calculated each time they are needed for a visualization or calculation.
Measures are useful for performing dynamic aggregations on data, such as sums, counts, averages, and so on.
In general, calculated columns are more resource-intensive, as the calculation is performed for every row in the table, and the result is stored.
Measures, on the other hand, are more flexible, as they can be calculated on the fly and updated in real-time as the underlying data changes.
When to use calculated columns and measures, there are some important points to be remember-
Large Data: As mentioned earlier, calculated columns can consume a large amount of memory and slow down the performance of your data model if your data volume is large.
Measures, on the other hand, perform calculations on-the-fly and only aggregate the data that is necessary for the current view.
Reusability: Measures are reusable and can be used in multiple visualizations and reports, while calculated columns are tied to a specific table and cannot be easily reused.
Update Frequency: Calculated columns are only updated when the data is refreshed, while measures are updated in real-time as the underlying data changes.
Data Types: Calculated columns can handle a wider variety of data types, including text and date/time values, while measures are limited to numeric data types.
Complexity: Measures can handle more complex calculations than calculated columns, including complex aggregations and dynamic calculations based on user selections and filters.