Line charts are a popular way to visualize data trends in SQL Server Reporting Services (SSRS). However, sometimes it’s helpful to add additional information to the chart, such as a trendline. In this article, we will explore how to add trendlines to line charts in SSRS.

What is a Trendline?

A trendline is a line that represents the general direction of a data series. It helps to identify patterns and trends in the data, making it easier to analyze and interpret the information. Trendlines can be useful in various scenarios, such as forecasting future values or identifying outliers.

Adding a Calculated Series

In SSRS, we can add a trendline to a line chart by creating a calculated series. A calculated series is a series where its data is derived from another series in the graph through a specific formula. This means that we don’t have to perform additional calculations in the source query.

To add a calculated series, right-click on the series you want to base the calculation on and select “Add Calculated Series…”. A dialog box will appear where you can select the type of formula you want to use. SSRS provides various formulas, such as mean, median, moving average, and more advanced formulas like Bollinger bands.

After selecting the formula, the new calculated series will be added to the graph. You can customize the series properties, such as visibility, axes, and borders, by accessing the “Calculated Series Properties” dialog.

Limitations and Missing Functionality

While SSRS offers a range of formulas for calculated series, one crucial trendline is missing: the linear regression. This means that if you want to add a linear trendline to your graph, you will need to perform the calculations yourself. Unfortunately, the official Microsoft documentation on calculated series is limited, providing only a list of available options without much explanation.

However, there are third-party tools available that provide more information on the different formulas and their usage in SSRS. These tools can be helpful in understanding and implementing more complex trendlines.

Conclusion

The calculated series feature in SSRS allows us to easily add trendlines to line charts, providing valuable insights into data trends. While there are many options available, such as moving averages, mean, median, and more advanced formulas, the lack of a linear regression trendline is a limitation. It is important to explore third-party resources for a deeper understanding of the available formulas and their implementation in SSRS.