Report Builder functions - Previous function in a paginated report (Report Builder)
Applies to: 
Microsoft Report Builder (SSRS)
Power BI Report Builder
Report Designer in SQL Server Data Tools
Returns the value or the specified aggregate value for the previous instance of an item within the specified scope in a paginated report.
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.
Syntax
Previous(expression, scope)
Parameters
expression
(Variant or Binary) The expression to use to identify the data and for which to retrieve the previous value, for example, Fields!Fieldname.Value or Sum(Fields!Fieldname.Value).
scope
(String) Optional. The name of a group or data region, or null (Nothing in Visual Basic), that specifies the scope from which to retrieve the previous value specified by expression.
Return Type
Returns a Variant or Binary.
Remarks
The Previous function returns the previous value for the expression evaluated in the specified scope after all sorting and filtering have been applied.
If expression does not contain an aggregate, the Previous function defaults to the current scope for the report item.
In a details group, use Previous to specify the value of a field reference in the previous instance of the detail row.
Note
The Previous function only supports field references in the details group. For example, in a text box in the details group, =Previous(Fields!Quantity.Value) returns the data for the field Quantity from the previous row. In the first row, this expression returns a null (Nothing in Visual Basic).
If expression contains an aggregate function that uses a default scope, Previous aggregates the data within the previous instance of the scope specified in the aggregate function call.
If expression contains an aggregate function that specifies a scope other than the default, the scope parameter for the Previous function must be a containing scope for the scope specified in the aggregate function call.
The functions Level, InScope, Aggregate and Previous cannot be used in the expression parameter. Specifying the recursive parameter for any aggregate function is not supported.
For more information, see Aggregate Functions Reference (Report Builder and SSRS) and Expression Scope for Totals, Aggregates, and Built-in Collections (Report Builder and SSRS).
Examples
Description
The following code example, when placed in the default data row of a data region, provides the value for the field LineTotal in the previous row.
Code
=Previous(Fields!LineTotal.Value)
Description
The following example shows an expression that calculates the sum of sales on a specific day of the month and the previous value for that day of the month in a previous year. The expression is added to a cell in a row that belongs to the child group GroupbyDay. Its parent group is GroupbyMonth, which has a parent group GroupbyYear. The expression displays the results for GroupbyDay (the default scope) and then for GroupbyYear (the parent of the parent group GroupbyMonth).
For example, for a data region with a parent group named Year, its child group named Month, and its child group named Day (3 nested levels). The expression =Previous(Sum(Fields!Sales.Value,"Day"),"Year") in a row associated with the group Day returns the sales value for the same day and month for the previous year.
Code
=Sum(Fields!Sales.Value) & " " & Previous(Sum(Fields!Sales.Value,"GroupbyDay"),"GroupbyYear")