prepare/execute return a wrong result after changing parameter's type

[qw4990]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

CREATE TABLE t (
  id bigint(20) NOT NULL,
  audit_id bigint(20) NOT NULL,
  PRIMARY KEY (id) /*T![clustered_index] CLUSTERED */,
  KEY index_audit_id (audit_id)
);

insert into t values(1,9941971237863475);
insert into t values(2,9941971237863476);

prepare stmt from 'select * from t where audit_id=?';
set @a='9941971237863475';
execute stmt using @a;
set @a=9941971237863475;
execute stmt using @a;

select * from t where audit_id='9941971237863475';
select * from t where audit_id=9941971237863475;

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

All execute and select statement should return the same result.

3. What did you see instead (Required)

mysql> prepare stmt from 'select * from t where audit_id=?';
Query OK, 0 rows affected (0.00 sec)

mysql> set @a='9941971237863475';
Query OK, 0 rows affected (0.00 sec)

mysql> execute stmt using @a;
+----+------------------+
| id | audit_id         |
+----+------------------+
|  1 | 9941971237863475 |
|  2 | 9941971237863476 |
+----+------------------+
2 rows in set (0.00 sec)

mysql> set @a=9941971237863475;
Query OK, 0 rows affected (0.00 sec)

mysql> execute stmt using @a;
+----+------------------+
| id | audit_id         |
+----+------------------+
|  1 | 9941971237863475 |
+----+------------------+
1 row in set (0.00 sec)

mysql> 
mysql> 
mysql> select * from t where audit_id='9941971237863475';
+----+------------------+
| id | audit_id         |
+----+------------------+
|  1 | 9941971237863475 |
+----+------------------+
1 row in set (0.01 sec)

mysql> select * from t where audit_id=9941971237863475;
+----+------------------+
| id | audit_id         |
+----+------------------+
|  1 | 9941971237863475 |
+----+------------------+
1 row in set (0.00 sec)

4. What is your TiDB version? (Required)

+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tidb_version()                                                                                                                                                                                                                                                                                                                   |
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Release Version: v5.3.0-alpha-1114-g06cfd000c-dirty
Edition: Community
Git Commit Hash: 06cfd000cb481d30c92a5917fd2734b37a7caffe
Git Branch: master
UTC Build Time: 2021-10-15 07:06:51
GoVersion: go1.16.3
Race Enabled: false
TiKV Min Version: v3.0.0-60965b006877ca7234adaced7890d7b029ed1306
Check Table Before Drop: false |
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

[github-actions]

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