fix materialized view aggregated functions

lib/active_record/connection_adapters/clickhouse_adapter.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require 'clickhouse-activerecord/arel/visitors/to_sql'
+require 'clickhouse-activerecord/arel/table'
 require 'active_record/connection_adapters/abstract_adapter'
 require 'active_record/connection_adapters/clickhouse/oid/date'
 require 'active_record/connection_adapters/clickhouse/oid/date_time'
@@ -30,6 +31,14 @@ def clickhouse_connection(config)
     end
   end
 
+  module TypeCaster
+    class Map
+      def is_view
+        types.is_view
+      end
+    end
+  end
+
   module ModelSchema
      module ClassMethods
       def is_view
@@ -39,6 +48,11 @@ def is_view
       def is_view=(value)
         @is_view = value
       end
+
+      def arel_table # :nodoc:
+        @arel_table ||= ClickhouseActiverecord::Arel::Table.new(table_name, type_caster: type_caster)
+      end
+
     end
    end
 
@@ -130,6 +144,10 @@ def quoted_date(value)
         value.to_s(:db)
       end
 
+      def column_name_for_operation(operation, node) # :nodoc:
+        column_name_from_arel_node(node)
+      end
+
       # Executes insert +sql+ statement in the context of this connection using
       # +binds+ as the bind substitutes. +name+ is logged along with
       # the executed +sql+ statement.

lib/clickhouse-activerecord/arel/table.rb

@@ -0,0 +1,9 @@
+module ClickhouseActiverecord
+  module Arel
+    class Table < ::Arel::Table
+      def is_view
+        type_caster.is_view
+      end
+    end
+  end
+end

lib/clickhouse-activerecord/arel/visitors/to_sql.rb

@@ -6,13 +6,12 @@ module Visitors
       class ToSql < ::Arel::Visitors::ToSql
 
         def aggregate(name, o, collector)
-          # todo how get model class from request? This method works with only rails 4.2.
           # replacing function name for materialized view
-          # if o.expressions.first && o.expressions.first != '*' && !o.expressions.first.is_a?(String) && o.expressions.first.relation && o.expressions.first.relation.engine && o.expressions.first.relation.engine.is_view
-          #   super("#{name.downcase}Merge", o, collector)
-          # else
+          if o.expressions.first && o.expressions.first != '*' && !o.expressions.first.is_a?(String) && o.expressions.first.relation&.is_view
+            super("#{name.downcase}Merge", o, collector)
+          else
             super
-          # end
+          end
         end
 
       end

lib/clickhouse-activerecord/version.rb

@@ -1,3 +1,3 @@
 module ClickhouseActiverecord
-  VERSION = '0.3.4'
+  VERSION = '0.3.5'
 end