query failed with index out of range [-1]

[windtalker]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

mysql> drop table if exists t1;
Query OK, 0 rows affected (0.51 sec)

mysql> drop table if exists t;
Query OK, 0 rows affected (0.52 sec)

mysql> create table t (a int not null, b int, c varchar(20));
Query OK, 0 rows affected (0.51 sec)

mysql> create table t1 (a int, b int not null, c double);
Query OK, 0 rows affected (0.51 sec)

mysql> alter table t set tiflash replica 1;
Query OK, 0 rows affected (0.51 sec)

mysql> alter table t1 set tiflash replica 1;
Query OK, 0 rows affected (0.51 sec)

mysql> explain select count(*) from (select a , b from t union all select a , c from t1 where false) tt;
+------------------------------------+----------+-------------------+---------------+-----------------------------------------------------+
| id                                 | estRows  | task              | access object | operator info                                       |
+------------------------------------+----------+-------------------+---------------+-----------------------------------------------------+
| HashAgg_33                         | 1.00     | root              |               | funcs:count(Column#14)->Column#11                   |
| └─TableReader_35                   | 1.00     | root              |               | data:ExchangeSender_34                              |
|   └─ExchangeSender_34              | 1.00     | batchCop[tiflash] |               | ExchangeType: PassThrough                           |
|     └─HashAgg_15                   | 1.00     | batchCop[tiflash] |               | funcs:count(1)->Column#14                           |
|       └─Union_32                   | 10000.00 | batchCop[tiflash] |               |                                                     |
|         └─Projection_51            | 10000.00 | batchCop[tiflash] |               | cast(Column#9, int(11) BINARY)->Column#9, Column#10 |
|           └─Projection_26          | 10000.00 | batchCop[tiflash] |               | test.t.a, cast(test.t.b, double BINARY)->Column#10  |
|             └─TableFullScan_27     | 10000.00 | batchCop[tiflash] | table:t       | keep order:false, stats:pseudo                      |
+------------------------------------+----------+-------------------+---------------+-----------------------------------------------------+
8 rows in set (0.00 sec)

mysql>  select count(*) from (select a , b from t union all select a , c from t1 where false) tt;
ERROR 1105 (HY000): runtime error: index out of range [-1]

2. What did you expect to see? (Required)

query executed without error

3. What did you see instead (Required)

ERROR 1105 (HY000): runtime error: index out of range [-1]

4. What is your TiDB version? (Required)

master@38e90ad13657ebe2cd2e2a2832aba26130b75e64

[yudongusa]

@windtalker assigning this issue to you as you've been fixing it via #28251

[github-actions]

Please check whether the issue should be labeled with 'affects-x.y' or 'fixes-x.y.z', and then remove 'needs-more-info' label.