diff --git a/executor/insert_test.go b/executor/insert_test.go
index b209330dabb67..8c20916d50708 100644
--- a/executor/insert_test.go
+++ b/executor/insert_test.go
@@ -883,3 +883,19 @@ func (s *testSuite3) TestIssue16366(c *C) {
 	c.Assert(err, NotNil)
 	c.Assert(strings.Contains(err.Error(), "Duplicate entry '0' for key 'PRIMARY'"), IsTrue, Commentf("%v", err))
 }
+
+func (s *testSuite3) TestIssue20768(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists t1, t2")
+	tk.MustExec("create table t1(a year, primary key(a))")
+	tk.MustExec("insert ignore into t1 values(null)")
+	tk.MustExec("create table t2(a int, key(a))")
+	tk.MustExec("insert into t2 values(0)")
+	tk.MustQuery("select /*+ hash_join(t1) */ * from t1 join t2 on t1.a = t2.a").Check(testkit.Rows("0 0"))
+	tk.MustQuery("select /*+ inl_join(t1) */ * from t1 join t2 on t1.a = t2.a").Check(testkit.Rows("0 0"))
+	tk.MustQuery("select /*+ inl_join(t2) */ * from t1 join t2 on t1.a = t2.a").Check(testkit.Rows("0 0"))
+	tk.MustQuery("select /*+ inl_hash_join(t1) */ * from t1 join t2 on t1.a = t2.a").Check(testkit.Rows("0 0"))
+	tk.MustQuery("select /*+ inl_merge_join(t1) */ * from t1 join t2 on t1.a = t2.a").Check(testkit.Rows("0 0"))
+	tk.MustQuery("select /*+ merge_join(t1) */ * from t1 join t2 on t1.a = t2.a").Check(testkit.Rows("0 0"))
+}
diff --git a/table/column.go b/table/column.go
index ebed7a1238d3a..4843185cc68ff 100644
--- a/table/column.go
+++ b/table/column.go
@@ -460,12 +460,14 @@ func getColDefaultValueFromNil(ctx sessionctx.Context, col *model.ColumnInfo) (t
 func GetZeroValue(col *model.ColumnInfo) types.Datum {
 	var d types.Datum
 	switch col.Tp {
-	case mysql.TypeTiny, mysql.TypeInt24, mysql.TypeShort, mysql.TypeLong, mysql.TypeLonglong, mysql.TypeYear:
+	case mysql.TypeTiny, mysql.TypeInt24, mysql.TypeShort, mysql.TypeLong, mysql.TypeLonglong:
 		if mysql.HasUnsignedFlag(col.Flag) {
 			d.SetUint64(0)
 		} else {
 			d.SetInt64(0)
 		}
+	case mysql.TypeYear:
+		d.SetInt64(0)
 	case mysql.TypeFloat:
 		d.SetFloat32(0)
 	case mysql.TypeDouble: