diff --git a/executor/aggregate_test.go b/executor/aggregate_test.go
index 1d5318e0498f2..56fe7f2df6611 100644
--- a/executor/aggregate_test.go
+++ b/executor/aggregate_test.go
@@ -770,7 +770,7 @@ func (s *testSuiteAgg) TestOnlyFullGroupBy(c *C) {
 	tk.MustQuery("select max(a+b) from t")
 	tk.MustQuery("select avg(a)+1 from t")
 	tk.MustQuery("select count(c), 5 from t")
-	// test functinal depend on primary key
+	// test functional depend on primary key
 	tk.MustQuery("select * from t group by a")
 	// test functional depend on unique not null columns
 	tk.MustQuery("select * from t group by b,d")
@@ -1441,3 +1441,14 @@ func (s *testSuiteAgg) TestIssue23277(c *C) {
 	tk.MustQuery("select avg(a) from t group by a").Sort().Check(testkit.Rows("-120.0000", "127.0000"))
 	tk.MustExec("drop table t;")
 }
+
+// https://github.com/pingcap/tidb/issues/23314
+func (s *testSuiteAgg) TestIssue23314(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists t1")
+	tk.MustExec("create table t1(col1 time(2) NOT NULL)")
+	tk.MustExec("insert into t1 values(\"16:40:20.01\")")
+	res := tk.MustQuery("select col1 from t1 group by col1")
+	res.Check(testkit.Rows("16:40:20.01"))
+}
diff --git a/expression/builtin_cast_vec.go b/expression/builtin_cast_vec.go
index 4ec1d138f8f41..e350d6154ce78 100644
--- a/expression/builtin_cast_vec.go
+++ b/expression/builtin_cast_vec.go
@@ -1304,12 +1304,13 @@ func (b *builtinCastDurationAsStringSig) vecEvalString(input *chunk.Chunk, resul
 	var isNull bool
 	sc := b.ctx.GetSessionVars().StmtCtx
 	result.ReserveString(n)
+	fsp := b.args[0].GetType().Decimal
 	for i := 0; i < n; i++ {
 		if buf.IsNull(i) {
 			result.AppendNull()
 			continue
 		}
-		res, err = types.ProduceStrWithSpecifiedTp(buf.GetDuration(i, 0).String(), b.tp, sc, false)
+		res, err = types.ProduceStrWithSpecifiedTp(buf.GetDuration(i, fsp).String(), b.tp, sc, false)
 		if err != nil {
 			return err
 		}