From f3791518d1660a988df83d86ed882ce4c4550463 Mon Sep 17 00:00:00 2001
From: ti-srebot <66930949+ti-srebot@users.noreply.github.com>
Date: Thu, 18 Mar 2021 19:01:36 +0800
Subject: [PATCH] expression: do not adjust int when it is null and compared
 year (#22821) (#22844)

---
 executor/executor_test.go     | 9 +++++++++
 expression/builtin_compare.go | 4 ++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/executor/executor_test.go b/executor/executor_test.go
index e310abc017c96..0e77b813485c1 100644
--- a/executor/executor_test.go
+++ b/executor/executor_test.go
@@ -6454,6 +6454,15 @@ func (s *testSuite) TestIssue20305(c *C) {
 	tk.MustQuery("SELECT * FROM `t3` where y <= a").Check(testkit.Rows("2155 2156"))
 }
 
+func (s *testSuite) TestIssue22817(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists t3")
+	tk.MustExec("create table t3 (a year)")
+	tk.MustExec("insert into t3 values (1991), (\"1992\"), (\"93\"), (94)")
+	tk.MustQuery("select * from t3 where a >= NULL").Check(testkit.Rows())
+}
+
 func (s *testSuite) TestIssue13953(c *C) {
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")
diff --git a/expression/builtin_compare.go b/expression/builtin_compare.go
index 671158a5e0138..72b71de7ac5ca 100644
--- a/expression/builtin_compare.go
+++ b/expression/builtin_compare.go
@@ -1373,7 +1373,7 @@ func (c *compareFunctionClass) refineArgs(ctx sessionctx.Context, args []Express
 		}
 	}
 	// int constant [cmp] year type
-	if arg0IsCon && arg0IsInt && arg1Type.Tp == mysql.TypeYear {
+	if arg0IsCon && arg0IsInt && arg1Type.Tp == mysql.TypeYear && !arg0.Value.IsNull() {
 		adjusted, failed := types.AdjustYear(arg0.Value.GetInt64(), false)
 		if failed == nil {
 			arg0.Value.SetInt64(adjusted)
@@ -1381,7 +1381,7 @@ func (c *compareFunctionClass) refineArgs(ctx sessionctx.Context, args []Express
 		}
 	}
 	// year type [cmp] int constant
-	if arg1IsCon && arg1IsInt && arg0Type.Tp == mysql.TypeYear {
+	if arg1IsCon && arg1IsInt && arg0Type.Tp == mysql.TypeYear && !arg1.Value.IsNull() {
 		adjusted, failed := types.AdjustYear(arg1.Value.GetInt64(), false)
 		if failed == nil {
 			arg1.Value.SetInt64(adjusted)