Change the interface of `having` to match that of `where`

These two clauses have nearly identical semantics with regards to how
they would be constructed as an AST. It doesn't make sense for their
interfaces to be separate.

6 files changed, 18 insertions, 16 deletions

diff --git a/lib/arel/nodes/select_core.rb b/lib/arel/nodes/select_core.rb
index 09ae420aa1..3696dd20af 100644
--- a/lib/arel/nodes/select_core.rb
+++ b/lib/arel/nodes/select_core.rb
@@ -2,7 +2,7 @@ module Arel
   module Nodes
     class SelectCore < Arel::Nodes::Node
       attr_accessor :top, :projections, :wheres, :groups, :windows
-      attr_accessor :having, :source, :set_quantifier
+      attr_accessor :havings, :source, :set_quantifier
 
       def initialize
         super()
@@ -14,7 +14,7 @@ module Arel
         @projections    = []
         @wheres         = []
         @groups         = []
-        @having         = nil
+        @havings        = []
         @windows        = []
       end
 
@@ -35,14 +35,14 @@ module Arel
         @projections = @projections.clone
         @wheres      = @wheres.clone
         @groups      = @groups.clone
-        @having      = @having.clone if @having
+        @havings     = @havings.clone
         @windows     = @windows.clone
       end
 
       def hash
         [
           @source, @top, @set_quantifier, @projections,
-          @wheres, @groups, @having, @windows
+          @wheres, @groups, @havings, @windows
         ].hash
       end
 
@@ -54,7 +54,7 @@ module Arel
           self.projections == other.projections &&
           self.wheres == other.wheres &&
           self.groups == other.groups &&
-          self.having == other.having &&
+          self.havings == other.havings &&
           self.windows == other.windows
       end
       alias :== :eql?
diff --git a/lib/arel/nodes/unary.rb b/lib/arel/nodes/unary.rb
index 3d4a4b014a..a0062ff5be 100644
--- a/lib/arel/nodes/unary.rb
+++ b/lib/arel/nodes/unary.rb
@@ -23,7 +23,6 @@ module Arel
     %w{
       Bin
       Group
-      Having
       Limit
       Not
       Offset
diff --git a/lib/arel/select_manager.rb b/lib/arel/select_manager.rb
index dd1ae37b65..e5fdbc887c 100644
--- a/lib/arel/select_manager.rb
+++ b/lib/arel/select_manager.rb
@@ -118,8 +118,8 @@ module Arel
       join(relation, Nodes::OuterJoin)
     end
 
-    def having *exprs
-      @ctx.having = Nodes::Having.new(collapse(exprs, @ctx.having))
+    def having expr
+      @ctx.havings << expr
       self
     end
 
diff --git a/lib/arel/visitors/depth_first.rb b/lib/arel/visitors/depth_first.rb
index d7d85cfcc6..22704dd038 100644
--- a/lib/arel/visitors/depth_first.rb
+++ b/lib/arel/visitors/depth_first.rb
@@ -146,7 +146,7 @@ module Arel
         visit o.wheres
         visit o.groups
         visit o.windows
-        visit o.having
+        visit o.havings
       end
 
       def visit_Arel_Nodes_SelectStatement o
diff --git a/lib/arel/visitors/informix.rb b/lib/arel/visitors/informix.rb
index 7e8a3ea458..c33ef50554 100644
--- a/lib/arel/visitors/informix.rb
+++ b/lib/arel/visitors/informix.rb
@@ -34,8 +34,13 @@ module Arel
           collector = inject_join o.groups, collector, ", "
         end
 
-        maybe_visit o.having, collector
+        if o.havings.any?
+          collector << " HAVING "
+          collector = inject_join o.havings, collector, " AND "
+        end
+        collector
       end
+
       def visit_Arel_Nodes_Offset o, collector
         collector << "SKIP "
         visit o.expr, collector
diff --git a/lib/arel/visitors/to_sql.rb b/lib/arel/visitors/to_sql.rb
index acf0a74d37..7dfa86a575 100644
--- a/lib/arel/visitors/to_sql.rb
+++ b/lib/arel/visitors/to_sql.rb
@@ -265,7 +265,10 @@ module Arel
           end
         end
 
-        collector = maybe_visit o.having, collector
+        unless o.havings.empty?
+          collector << " HAVING "
+          inject_join o.havings, collector, AND
+        end
 
         unless o.windows.empty?
           collector << WINDOW
@@ -404,11 +407,6 @@ module Arel
         end
       end
 
-      def visit_Arel_Nodes_Having o, collector
-        collector << "HAVING "
-        visit o.expr, collector
-      end
-
       def visit_Arel_Nodes_Offset o, collector
         collector << "OFFSET "
         visit o.expr, collector