refactoring expressions to a module

1 files changed, 23 insertions, 0 deletions

diff --git a/lib/arel/expressions.rb b/lib/arel/expressions.rb
new file mode 100644
index 0000000000..d1fbfd83d9
--- /dev/null
+++ b/lib/arel/expressions.rb
@@ -0,0 +1,23 @@
+module Arel
+  module Expressions
+    def count distinct = false
+      Nodes::Count.new [self], distinct
+    end
+
+    def sum
+      Nodes::Sum.new [self], Nodes::SqlLiteral.new('sum_id')
+    end
+
+    def maximum
+      Nodes::Max.new [self], Nodes::SqlLiteral.new('max_id')
+    end
+
+    def minimum
+      Nodes::Min.new [self], Nodes::SqlLiteral.new('min_id')
+    end
+
+    def average
+      Nodes::Avg.new [self], Nodes::SqlLiteral.new('avg_id')
+    end
+  end
+end