diff --git a/executor/executor_test.go b/executor/executor_test.go
index 85d0dad290bb0..422956d045abe 100644
--- a/executor/executor_test.go
+++ b/executor/executor_test.go
@@ -2114,6 +2114,8 @@ func TestIncorrectLimitArg(t *testing.T) {
 
 	tk.MustGetErrMsg(`execute stmt1 using @a;`, `[planner:1210]Incorrect arguments to LIMIT`)
 	tk.MustGetErrMsg(`execute stmt2 using @b, @a;`, `[planner:1210]Incorrect arguments to LIMIT`)
+	tk.MustGetErrMsg(`execute stmt2 using @a, @b;`, `[planner:1210]Incorrect arguments to LIMIT`)
+	tk.MustGetErrMsg(`execute stmt2 using @a, @a;`, `[planner:1210]Incorrect arguments to LIMIT`)
 }
 
 func TestExecutorLimit(t *testing.T) {
diff --git a/executor/seqtest/prepared_test.go b/executor/seqtest/prepared_test.go
index 5811a386f137d..3c0f180e54f22 100644
--- a/executor/seqtest/prepared_test.go
+++ b/executor/seqtest/prepared_test.go
@@ -826,6 +826,12 @@ func TestSetPlanCacheLimitSwitch(t *testing.T) {
 
 	tk.MustExec("set @@global.tidb_enable_plan_cache_for_param_limit = ON;")
 	tk.MustQuery("select @@global.tidb_enable_plan_cache_for_param_limit").Check(testkit.Rows("1"))
+
+	tk.MustGetErrMsg("set @@global.tidb_enable_plan_cache_for_param_limit = '';", "[variable:1231]Variable 'tidb_enable_plan_cache_for_param_limit' can't be set to the value of ''")
+	tk.MustGetErrMsg("set @@global.tidb_enable_plan_cache_for_param_limit = 11;", "[variable:1231]Variable 'tidb_enable_plan_cache_for_param_limit' can't be set to the value of '11'")
+	tk.MustGetErrMsg("set @@global.tidb_enable_plan_cache_for_param_limit = enabled;", "[variable:1231]Variable 'tidb_enable_plan_cache_for_param_limit' can't be set to the value of 'enabled'")
+	tk.MustGetErrMsg("set @@global.tidb_enable_plan_cache_for_param_limit = disabled;", "[variable:1231]Variable 'tidb_enable_plan_cache_for_param_limit' can't be set to the value of 'disabled'")
+	tk.MustGetErrMsg("set @@global.tidb_enable_plan_cache_for_param_limit = open;", "[variable:1231]Variable 'tidb_enable_plan_cache_for_param_limit' can't be set to the value of 'open'")
 }
 
 func TestPlanCacheLimitSwitchEffective(t *testing.T) {
diff --git a/planner/core/plan_cache_test.go b/planner/core/plan_cache_test.go
index 9f8ff161fd658..e3a0d276e9815 100644
--- a/planner/core/plan_cache_test.go
+++ b/planner/core/plan_cache_test.go
@@ -469,6 +469,8 @@ func TestPlanCacheWithLimit(t *testing.T) {
 		params []int
 	}{
 		{"prepare stmt from 'select * from t limit ?'", []int{1}},
+		{"prepare stmt from 'select * from t limit 1, ?'", []int{1}},
+		{"prepare stmt from 'select * from t limit ?, 1'", []int{1}},
 		{"prepare stmt from 'select * from t limit ?, ?'", []int{1, 2}},
 		{"prepare stmt from 'delete from t order by a limit ?'", []int{1}},
 		{"prepare stmt from 'insert into t select * from t order by a desc limit ?'", []int{1}},
@@ -491,7 +493,8 @@ func TestPlanCacheWithLimit(t *testing.T) {
 		tk.MustExec("execute stmt using " + strings.Join(using, ", "))
 		tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("1"))
 
-		if idx < 6 {
+		if idx < 9 {
+			// none point get plan
 			tk.MustExec("set @a0 = 6")
 			tk.MustExec("execute stmt using " + strings.Join(using, ", "))
 			tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("0"))