1 files changed, 6 insertions, 10 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
index 98916b06a5..3fce8de1ba 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
@@ -384,8 +384,9 @@ module ActiveRecord
         def change_column(table_name, column_name, type, options = {})
           clear_cache!
           quoted_table_name = quote_table_name(table_name)
-
-          execute "ALTER TABLE #{quoted_table_name} ALTER COLUMN #{quote_column_name(column_name)} TYPE #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
+          sql_type = type_to_sql(type, options[:limit], options[:precision], options[:scale])
+          sql_type << "[]" if options[:array]
+          execute "ALTER TABLE #{quoted_table_name} ALTER COLUMN #{quote_column_name(column_name)} TYPE #{sql_type}"
 
           change_column_default(table_name, column_name, options[:default]) if options_include_default?(options)
           change_column_null(table_name, column_name, options[:null], options[:default]) if options.key?(:null)
@@ -467,22 +468,17 @@ module ActiveRecord
           end
         end
 
-        # Returns a SELECT DISTINCT clause for a given set of columns and a given ORDER BY clause.
-        #
         # PostgreSQL requires the ORDER BY columns in the select list for distinct queries, and
         # requires that the ORDER BY include the distinct column.
-        #
-        #   distinct("posts.id", ["posts.created_at desc"])
-        #   # => "DISTINCT posts.id, posts.created_at AS alias_0"
-        def distinct(columns, orders) #:nodoc:
-          order_columns = orders.map{ |s|
+        def columns_for_distinct(columns, orders) #:nodoc:
+          order_columns = orders.reject(&:blank?).map{ |s|
               # Convert Arel node to string
               s = s.to_sql unless s.is_a?(String)
               # Remove any ASC/DESC modifiers
               s.gsub(/\s+(ASC|DESC)\s*(NULLS\s+(FIRST|LAST)\s*)?/i, '')
             }.reject(&:blank?).map.with_index { |column, i| "#{column} AS alias_#{i}" }
 
-          [super].concat(order_columns).join(', ')
+          [super, *order_columns].join(', ')
         end
       end
     end