1 files changed, 2 insertions, 4 deletions
diff --git a/activerecord/lib/active_record/validations/uniqueness.rb b/activerecord/lib/active_record/validations/uniqueness.rb
index e28808df98..4806fa0ecc 100644
--- a/activerecord/lib/active_record/validations/uniqueness.rb
+++ b/activerecord/lib/active_record/validations/uniqueness.rb
@@ -67,13 +67,11 @@ module ActiveRecord
 
         if value.nil? || (options[:case_sensitive] || !column.text?)
           sql = "#{sql_attribute} #{operator}"
-          params = [value]
         else
-          sql = "LOWER(#{sql_attribute}) #{operator}"
-          params = [value.mb_chars.downcase]
+          sql = "LOWER(#{sql_attribute}) = LOWER(?)"
         end
 
-        [sql, params]
+        [sql, [value]]
       end
     end