Expression reference in a paginated report (Report Builder)
Applies to: 
Microsoft Report Builder (SSRS)
Power BI Report Builder
Report Designer in SQL Server Data Tools
Paginated report expressions support a variety of references to built-in functions and built-in collections. Expressions must have valid Visual Basic syntax before a report can be published or processed.
To develop complex expressions or expressions that use custom code or custom assemblies, we recommend that you use Report Designer in SQL Server Data Tools (SSDT). For more information, see Custom Code and Assembly References in Expressions in Report Designer (SSRS).
Note
You can create and modify paginated report definition (.rdl) files in Microsoft Report Builder, Power BI Report Builder, and in Report Designer in SQL Server Data Tools.
Use the topics in this section to help write simple expressions in a report.
In This Section
Data Types in Expressions (Report Builder and SSRS)
Constants in Expressions (Report Builder and SSRS)
Operators in Expressions (Report Builder and SSRS)
Built-in Collections in Expressions (Report Builder and SSRS)
Built-in Globals and Users References (Report Builder and SSRS)
Parameters Collection References (Report Builder and SSRS)
Dataset Fields Collection References (Report Builder and SSRS)
DataSources and DataSets Collection References (Report Builder and SSRS)
Report and Group Variables Collections References (Report Builder and SSRS)
ReportItems Collection References (Report Builder and SSRS)