diff --git a/app/models/quantity.rb b/app/models/quantity.rb
index bd8ce0b..e8d36d3 100644
--- a/app/models/quantity.rb
+++ b/app/models/quantity.rb
@@ -61,24 +61,26 @@ class Quantity < ApplicationRecord
 
   # Return: ordered [sub]hierarchy
   scope :ordered, ->(root: nil, include_root: true) {
-    numbered = Arel::Table.new('numbered')
-
-    path_expr = if connection.adapter_name =~ /mysql/i
-      numbered.cast(numbered[:child_number], 'BINARY')
+    if connection.adapter_name =~ /mysql/i
+      numbered = Arel::Table.new('numbered')
+      self.model.with(numbered: numbered(:parent_id, :name)).with_recursive(arel_table.name => [
+        numbered.project(
+          numbered[Arel.star],
+          numbered.cast(numbered[:child_number], 'BINARY').as('path')
+        ).where(numbered[root && include_root ? :id : :parent_id].eq(root)),
+        numbered.project(
+          numbered[Arel.star],
+          arel_table[:path].concat(numbered[:child_number])
+        ).join(arel_table).on(numbered[:parent_id].eq(arel_table[:id]))
+      ]).order(arel_table[:path])
+    elsif root.nil?
+      # SQLite: pathname column already stores the full hierarchical path
+      order(:pathname)
     else
-      numbered[:child_number]
+      root_pathname = unscoped.where(id: root).pick(:pathname)
+      scope = order(:pathname).where("pathname LIKE ?", "#{root_pathname}#{PATHNAME_DELIMITER}%")
+      include_root ? scope.or(where(id: root)) : scope
     end
-
-    self.model.with(numbered: numbered(:parent_id, :name)).with_recursive(arel_table.name => [
-      numbered.project(
-        numbered[Arel.star],
-        path_expr.as('path')
-      ).where(numbered[root && include_root ? :id : :parent_id].eq(root)),
-      numbered.project(
-        numbered[Arel.star],
-        arel_table[:path].concat(numbered[:child_number])
-      ).join(arel_table).on(numbered[:parent_id].eq(arel_table[:id]))
-    ]).order(arel_table[:path])
   }
 
   # TODO: extract named functions to custom Arel extension
@@ -86,25 +88,20 @@ class Quantity < ApplicationRecord
   # be merged with :ordered
   # https://gist.github.com/ProGM/c6df08da14708dcc28b5ca325df37ceb#extending-arel
   scope :numbered, ->(parent_column, order_column) {
-    row_num = Arel::Nodes::NamedFunction.new('ROW_NUMBER', [])
-      .over(Arel::Nodes::Window.new.partition(parent_column).order(order_column))
-
-    child_number = if connection.adapter_name =~ /mysql/i
+    select(
+      arel_table[Arel.star],
       Arel::Nodes::NamedFunction.new(
         'LPAD',
         [
-          row_num,
+          Arel::Nodes::NamedFunction.new('ROW_NUMBER', [])
+            .over(Arel::Nodes::Window.new.partition(parent_column).order(order_column)),
           Arel::SelectManager.new.project(
             Arel::Nodes::NamedFunction.new('LENGTH', [Arel.star.count])
           ).from(arel_table),
           Arel::Nodes.build_quoted('0')
-        ]
-      )
-    else
-      Arel::Nodes::NamedFunction.new('format', [Arel::Nodes.build_quoted('%09d'), row_num])
-    end
-
-    select(arel_table[Arel.star], child_number.as('child_number'))
+        ],
+      ).as('child_number')
+    )
   }
 
   def to_s