Use IS [NOT] NULL instead of DBMS_LOB.COMPARE for nil CLOB/BLOB queries

lib/arel/visitors/oracle_common.rb

@@ -9,7 +9,9 @@ module OracleCommon
         # Fixes ORA-00932: inconsistent datatypes: expected - got CLOB
         def visit_Arel_Nodes_Equality(o, collector)
           left = o.left
+
           return super unless %i(text binary).include?(cached_column_for(left)&.type)
+          return super if o.right.nil?
 
           # https://docs.oracle.com/cd/B19306_01/appdev.102/b14258/d_lob.htm#i1016668
           # returns 0 when the comparison succeeds

spec/active_record/oracle_enhanced/type/binary_spec.rb

@@ -116,4 +116,25 @@ class ::TestEmployee < ActiveRecord::Base
     @employee.reload
     expect(@employee.binary_data).to eq(@binary_data)
   end
+
+  it "should find serialized NULL BLOB data when queried with nil" do
+    TestEmployee.delete_all
+    TestEmployee.create!(binary_data: nil)
+    TestEmployee.create!(binary_data: @binary_data)
+    expect(TestEmployee.where(binary_data: nil)).to have_attributes(count: 1)
+  end
+
+  it "should find serialized NULL BLOB data when queried with nil" do
+    TestSerializedHashEmployee.delete_all
+    TestSerializedHashEmployee.create!(binary_data: nil)
+    TestSerializedHashEmployee.create!(binary_data: { data: 'some data' })
+    expect(TestSerializedHashEmployee.where(binary_data: nil)).to have_attributes(count: 1)
+  end
+
+  it "should find serialized NULL BLOB data when queried with {}" do
+    TestSerializedHashEmployee.delete_all
+    TestSerializedHashEmployee.create!(binary_data: nil)
+    TestSerializedHashEmployee.create!(binary_data: { data: 'some data' })
+    expect(TestSerializedHashEmployee.where(binary_data: {})).to have_attributes(count: 1)
+  end
 end

spec/active_record/oracle_enhanced/type/text_spec.rb

@@ -241,4 +241,25 @@ class ::TestSerializeEmployee < ActiveRecord::Base
     )
     expect(Test2Employee.where(comments: search_data)).to have_attributes(count: 1)
   end
+
+  it "should find NULL CLOB data when queried with nil" do
+    TestEmployee.delete_all
+    TestEmployee.create!(comments: nil)
+    TestEmployee.create!(comments: @char_data)
+    expect(TestEmployee.where(comments: nil)).to have_attributes(count: 1)
+  end
+
+  it "should find serialized NULL CLOB data when queried with nil" do
+    Test2Employee.delete_all
+    Test2Employee.create!(comments: nil)
+    Test2Employee.create!(comments: { some: 'text' })
+    expect(Test2Employee.where(comments: nil)).to have_attributes(count: 1)
+  end
+
+  it "should find serialized NULL CLOB data when queried with {}" do
+    TestSerializedHashEmployee.delete_all
+    TestSerializedHashEmployee.create!(comments: nil)
+    TestSerializedHashEmployee.create!(comments: { some: 'text' })
+    expect(TestSerializedHashEmployee.where(comments: {})).to have_attributes(count: 1)
+  end
 end