diff --git a/test/test_core.py b/test/test_core.py
index fd7bb51..2d99a18 100644
--- a/test/test_core.py
+++ b/test/test_core.py
@@ -214,19 +214,37 @@ def define_tables(cls, metadata):
             Column("val", Integer),
         )
 
-    def test_1(self, connection):
+    def test_string(self, connection):
         tb = self.tables.test_upsert
 
         stm = ydb_sa.upsert(tb).values(id=5, val=5)
 
-        # TODO: allow to get string
-        # assert "UPSERT INTO" in str(stm)
+        assert "UPSERT INTO" in str(stm)
+
+    def test_upsert_new_id(self, connection):
+        tb = self.tables.test_upsert
+
+        stm = ydb_sa.upsert(tb).values(id=1, val=1)
 
         connection.execute(stm)
-        row = connection.execute(sa.select(tb)).fetchone()
-        assert row == (5, 5)
+        row = connection.execute(sa.select(tb)).fetchall()
+        assert row == [(1, 1)]
+
+        stm = ydb_sa.upsert(tb).values(id=2, val=2)
+        connection.execute(stm)
+        row = connection.execute(sa.select(tb)).fetchall()
+        assert row == [(1, 1), (2, 2)]
+
+    def test_upsert_existing_id(self, connection):
+        tb = self.tables.test_upsert
+
+        stm = ydb_sa.upsert(tb).values(id=5, val=5)
+
+        connection.execute(stm)
+        row = connection.execute(sa.select(tb)).fetchall()
+        assert row == [(5, 5)]
 
         stm = ydb_sa.upsert(tb).values(id=5, val=6)
         connection.execute(stm)
-        row = connection.execute(sa.select(tb)).fetchone()
-        assert row == (5, 6)
+        row = connection.execute(sa.select(tb)).fetchall()
+        assert row == [(5, 6)]
diff --git a/ydb_sqlalchemy/sqlalchemy/__init__.py b/ydb_sqlalchemy/sqlalchemy/__init__.py
index 61f293d..ddc0dea 100644
--- a/ydb_sqlalchemy/sqlalchemy/__init__.py
+++ b/ydb_sqlalchemy/sqlalchemy/__init__.py
@@ -342,13 +342,15 @@ def get_bind_types(
 
         return parameter_types
 
+    def visit_upsert(self, insert_stmt, visited_bindparam=None, **kw):
+        return self.visit_insert(insert_stmt, visited_bindparam, **kw).replace("INSERT", "UPSERT")
+
 
 class YqlDDLCompiler(DDLCompiler):
     pass
 
 
 def upsert(table):
-    # return sa.sql.Insert(table)
     return Upsert(table)
 
 
diff --git a/ydb_sqlalchemy/sqlalchemy/dml.py b/ydb_sqlalchemy/sqlalchemy/dml.py
index 8672c36..b2eabaf 100644
--- a/ydb_sqlalchemy/sqlalchemy/dml.py
+++ b/ydb_sqlalchemy/sqlalchemy/dml.py
@@ -8,16 +8,9 @@
 class Upsert(sa.sql.Insert):
     __visit_name__ = "upsert"
     _propagate_attrs = {"compile_state_plugin": "yql"}
-
-    def compile(
-        self,
-        bind=None,
-        dialect=None,
-        **kw: Any,
-    ):
-        return super(Upsert, self).compile(bind, **kw)
+    stringify_dialect = "yql"
 
 
 @sa.sql.base.CompileState.plugin_for("yql", "upsert")
-class InsertDMLState(sa.sql.dml.InsertDMLState):
+class UpsertDMLState(sa.sql.dml.InsertDMLState):
     pass