last_value for bit type incompatible with mysql

[aytrack]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

drop table if exists t1;
create table t1(a bit(7));
insert into t1 values (126);
select sum(a) over w, last_value(a) over w from t1 window w as (partition by a);
insert into t1 values (127);
select sum(a) over w, last_value(a) over w from t1 window w as (partition by a);

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

mysql> select sum(a) over w, last_value(a) over w from t1 window w as (partition by a);
Field   1:  `sum(a) over w`
Catalog:    `def`
Database:   ``
Table:      ``
Org_table:  ``
Type:       NEWDECIMAL
Collation:  binary (63)
Length:     30
Max_length: 3
Decimals:   0
Flags:      NUM

Field   2:  `last_value(a) over w`
Catalog:    `def`
Database:   ``
Table:      ``
Org_table:  ``
Type:       LONG
Collation:  binary (63)
Length:     7
Max_length: 3
Decimals:   0
Flags:      UNSIGNED NUM


+---------------+----------------------+
| sum(a) over w | last_value(a) over w |
+---------------+----------------------+
|           126 |                  126 |
|           127 |                  127 |
+---------------+----------------------+

3. What did you see instead (Required)

mysql> select sum(a) over w, last_value(a) over w from t1 window w as (partition by a);
Field   1:  `sum(a) over w`
Catalog:    `def`
Database:   ``
Table:      ``
Org_table:  ``
Type:       DOUBLE
Collation:  binary (63)
Length:     23
Max_length: 3
Decimals:   31
Flags:      NOT_NULL BINARY NUM

Field   2:  `last_value(a) over w`
Catalog:    `def`
Database:   ``
Table:      ``
Org_table:  ``
Type:       BIT
Collation:  binary (63)
Length:     7
Max_length: 1
Decimals:   0
Flags:      UNSIGNED


+---------------+----------------------+
| sum(a) over w | last_value(a) over w |
+---------------+----------------------+
|           126 | ~                    |
|           127 |                     |
+---------------+----------------------+
2 rows in set (0.04 sec)

4. What is your TiDB version? (Required)

master: ed52601
release-5.1： befa712

[aytrack]

nth_value has the same problem

mysql> select sum(a) over w, nth_value(a, 1) over w from t1 window w as (partition by a);
Field   1:  `sum(a) over w`
Catalog:    `def`
Database:   ``
Table:      ``
Org_table:  ``
Type:       DOUBLE
Collation:  binary (63)
Length:     23
Max_length: 3
Decimals:   31
Flags:      NOT_NULL BINARY NUM

Field   2:  `nth_value(a, 1) over w`
Catalog:    `def`
Database:   ``
Table:      ``
Org_table:  ``
Type:       BIT
Collation:  binary (63)
Length:     7
Max_length: 1
Decimals:   0
Flags:      UNSIGNED


+---------------+------------------------+
| sum(a) over w | nth_value(a, 1) over w |
+---------------+------------------------+
|           126 | ~                      |
|           127 |                       |
+---------------+------------------------+
2 rows in set (0.05 sec)

MySQL:

mysql> select sum(a) over w, nth_value(a, 1) over w from t1 window w as (partition by a);
Field   1:  `sum(a) over w`
Catalog:    `def`
Database:   ``
Table:      ``
Org_table:  ``
Type:       NEWDECIMAL
Collation:  binary (63)
Length:     30
Max_length: 3
Decimals:   0
Flags:      NUM

Field   2:  `nth_value(a, 1) over w`
Catalog:    `def`
Database:   ``
Table:      ``
Org_table:  ``
Type:       LONG
Collation:  binary (63)
Length:     7
Max_length: 3
Decimals:   0
Flags:      UNSIGNED NUM


+---------------+------------------------+
| sum(a) over w | nth_value(a, 1) over w |
+---------------+------------------------+
|           126 |                    126 |
|           127 |                    127 |
+---------------+------------------------+
2 rows in set (0.05 sec)