diff --git a/app/models/queries/work_packages/selects/work_package_select.rb b/app/models/queries/work_packages/selects/work_package_select.rb
index f52df5347d9f..90ed98e5f530 100644
--- a/app/models/queries/work_packages/selects/work_package_select.rb
+++ b/app/models/queries/work_packages/selects/work_package_select.rb
@@ -54,12 +54,10 @@ def self.scoped_column_sum(scope, select, grouped:, query:)
     scope = scope.except(:order, :select)
 
     if grouped
-      group_by = query.group_by_statement
-
       scope
         .joins(query.group_by_join_statement)
-        .group(group_by)
-        .select(select_group_by(group_by), select)
+        .group(query.group_by_statement)
+        .select(select_group_by(query.group_by_select), select)
     else
       scope
         .select(select)
diff --git a/app/models/query/results/sums.rb b/app/models/query/results/sums.rb
index 27e735d4f204..d349e199f2f9 100644
--- a/app/models/query/results/sums.rb
+++ b/app/models/query/results/sums.rb
@@ -109,7 +109,7 @@ def sums_callable_joins(grouped)
   def sums_work_package_scope_selects(grouped)
     group_statement =
       if grouped
-        [Queries::WorkPackages::Selects::WorkPackageSelect.select_group_by(query.group_by_statement)]
+        [Queries::WorkPackages::Selects::WorkPackageSelect.select_group_by(query.group_by_select)]
       else
         []
       end
diff --git a/modules/costs/spec/lib/costs/query_currency_select_spec.rb b/modules/costs/spec/lib/costs/query_currency_select_spec.rb
index 26ecf739d7de..8139e7f1c884 100644
--- a/modules/costs/spec/lib/costs/query_currency_select_spec.rb
+++ b/modules/costs/spec/lib/costs/query_currency_select_spec.rb
@@ -93,6 +93,7 @@
         allow(query).to receive_messages(
           results: result,
           group_by_join_statement: nil,
+          group_by_select: "author_id",
           group_by_statement: "author_id"
         )
 
@@ -130,6 +131,7 @@
         allow(query).to receive_messages(
           results: result,
           group_by_join_statement: nil,
+          group_by_select: "author_id",
           group_by_statement: "author_id"
         )