diff --git a/lib/pgsync/task.rb b/lib/pgsync/task.rb
index ed4add6..d234d52 100644
--- a/lib/pgsync/task.rb
+++ b/lib/pgsync/task.rb
@@ -111,8 +111,14 @@ def sync_data
           where = "#{quote_ident(primary_key)} >= #{starting_id} AND #{quote_ident(primary_key)} < #{starting_id + batch_size}"
           log "    #{i}/#{batch_count}: #{where}"
 
-          # TODO be smarter for advance sql clauses
-          batch_sql_clause = " #{sql_clause.length > 0 ? "#{sql_clause} AND" : "WHERE"} #{where}"
+          # Apply the batch range to the complete filter, not just its last OR term.
+          batch_sql_clause =
+            if sql_clause.length > 0
+              where_clause = sql_clause.sub(/\A\s*where\b/i, "")
+              " WHERE (#{where_clause}) AND (#{where})"
+            else
+              " WHERE #{where}"
+            end
 
           batch_copy_to_command = "COPY (SELECT #{copy_fields} FROM #{quoted_table}#{batch_sql_clause}) TO STDOUT"
           copy(batch_copy_to_command, dest_table: table, dest_fields: fields)
diff --git a/test/in_batches_test.rb b/test/in_batches_test.rb
index c6c40a9..0e8584c 100644
--- a/test/in_batches_test.rb
+++ b/test/in_batches_test.rb
@@ -12,6 +12,18 @@ def test_works
     assert_result("--in-batches --batch-size 1", source, dest, expected)
   end
 
+  def test_where_clause_with_or
+    source = 3.times.map { |i| {"id" => i + 1, "title" => "Post #{i + 1}"} }
+    expected = [source[0], source[2]]
+    assert_result("\"where id = 1 OR id = 3\" --in-batches --batch-size 1", source, [], expected)
+  end
+
+  def test_where_clause_without_space
+    source = 3.times.map { |i| {"id" => i + 1, "title" => "Post #{i + 1}"} }
+    expected = [source[0], source[2]]
+    assert_result("\"where(id = 1 OR id = 3)\" --in-batches --batch-size 1", source, [], expected)
+  end
+
   def test_existing_data
     source = 3.times.map { |i| {"id" => i + 1, "title" => "Post #{i + 1}"} }
     dest = [{"id" => 1, "title" => "First Post"}, {"id" => 4, "title" => "Post 4"}]