Collapse where constraints to one where constraint

In order to remove duplication with joining arel where constraints with
`AND`, all constraints on `build_arel` are collapsed into one head node: `Arel::Nodes::And`

Closes: #11963

1 files changed, 5 insertions, 6 deletions

diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb
index 1c6ea94c0b..5d0df32582 100644
--- a/activerecord/lib/active_record/relation/query_methods.rb
+++ b/activerecord/lib/active_record/relation/query_methods.rb
@@ -882,14 +882,13 @@ module ActiveRecord
     end
 
     def collapse_wheres(arel, wheres)
-      equalities = wheres.grep(Arel::Nodes::Equality)
-
-      arel.where(Arel::Nodes::And.new(equalities)) unless equalities.empty?
-
-      (wheres - equalities).each do |where|
+      predicates = wheres.map do |where|
+        next where if ::Arel::Nodes::Equality === where
         where = Arel.sql(where) if String === where
-        arel.where(Arel::Nodes::Grouping.new(where))
+        Arel::Nodes::Grouping.new(where)
       end
+
+      arel.where(Arel::Nodes::And.new(predicates)) if predicates.present?
     end
 
     def build_where(opts, other = [])