planner: fix prepare explain index out of range bug (#40568) (#40602)

close #38323

executor/seqtest/prepared_test.go

@@ -937,3 +937,21 @@ func TestPreparedIssue17419(t *testing.T) {
 	// _, ok := tk1.Session().ShowProcess().Plan.(*plannercore.Execute)
 	// require.True(t, ok)
 }
+
+func TestIssue38323(t *testing.T) {
+	store, _, clean := testkit.CreateMockStoreAndDomain(t)
+	defer clean()
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists t")
+	tk.MustExec("create table t(id int, k int);")
+
+	tk.MustExec("prepare stmt from 'explain select * from t where id = ? and k = ? group by id, k';")
+	tk.MustExec("set @a = 1;")
+	tk.MustExec("execute stmt using @a, @a")
+	tk.MustQuery("execute stmt using @a, @a").Check(tk.MustQuery("explain select * from t where id = 1 and k = 1 group by id, k").Rows())
+
+	tk.MustExec("prepare stmt from 'explain select * from t where ? = id and ? = k group by id, k';")
+	tk.MustExec("set @a = 1;")
+	tk.MustQuery("execute stmt using @a, @a").Check(tk.MustQuery("explain select * from t where 1 = id and 1 = k group by id, k").Rows())
+}

planner/core/point_get_plan.go

@@ -1207,7 +1207,7 @@ func getNameValuePairs(ctx sessionctx.Context, tbl *model.TableInfo, tblName mod
 			case *driver.ValueExpr:
 				d = x.Datum
 			case *driver.ParamMarkerExpr:
-				con, err = expression.ParamMarkerExpression(ctx, x, true)
+				con, err = expression.ParamMarkerExpression(ctx, x, false)
 				if err != nil {
 					return nil, false
 				}
@@ -1221,7 +1221,7 @@ func getNameValuePairs(ctx sessionctx.Context, tbl *model.TableInfo, tblName mod
 			case *driver.ValueExpr:
 				d = x.Datum
 			case *driver.ParamMarkerExpr:
-				con, err = expression.ParamMarkerExpression(ctx, x, true)
+				con, err = expression.ParamMarkerExpression(ctx, x, false)
 				if err != nil {
 					return nil, false
 				}