Date function is not compatible with Mysql

[hequn8128]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

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

mysql: 8.0.23

mysql> SELECT DATE_FORMAT("0000-02-28",'%W %d %M %Y') as valid_date;
+--------------------------+
| valid_date               |
+--------------------------+
| Tuesday 28 February 0000 |
+--------------------------+
1 row in set (0.00 sec)

mysql> SELECT DATE_FORMAT("0000-01-01",'%W %d %M %Y') as valid_date;
+------------------------+
| valid_date             |
+------------------------+
| Sunday 01 January 0000 |
+------------------------+
1 row in set (0.00 sec)

mysql> select str_to_date("2003-01-02 10:11:12.0012", "%Y-%m-%d %H:%i:%S.%f") as f1,
    -> str_to_date("2003-01-02 10:11:12.0012", "%Y-%m-%d %H:%i:%S") as f2,
    -> str_to_date("2003-01-02", "%Y-%m-%d") as f3,
    -> str_to_date("02 10:11:12", "%d %H:%i:%S.%f") as f4,
    -> str_to_date("02 10:11:12", "%d %H:%i:%S") as f5,
    -> str_to_date("02 10", "%d %f") as f6;
+----------------------------+---------------------+------------+-----------------+----------+-----------------+
| f1                         | f2                  | f3         | f4              | f5       | f6              |
+----------------------------+---------------------+------------+-----------------+----------+-----------------+
| 2003-01-02 10:11:12.001200 | 2003-01-02 10:11:12 | 2003-01-02 | 58:11:12.000000 | 58:11:12 | 48:00:00.100000 |
+----------------------------+---------------------+------------+-----------------+----------+-----------------+
1 row in set, 1 warning (0.02 sec)

mysql> select str_to_date("2003-....01ABCD-02 10:11:12.0012", "%Y-%.%m%@-%d %H:%i:%S.%f") as a;
+----------------------------+
| a                          |
+----------------------------+
| 2003-01-02 10:11:12.001200 |
+----------------------------+
1 row in set (0.00 sec)

3. What did you see instead (Required)

mysql> SELECT DATE_FORMAT("0000-02-28",'%W %d %M %Y') as valid_date;
+-------------------------+
| valid_date              |
+-------------------------+
| Monday 28 February 0000 |
+-------------------------+
1 row in set (0.00 sec)

mysql> SELECT DATE_FORMAT("0000-01-01",'%W %d %M %Y') as valid_date;
+--------------------------+
| valid_date               |
+--------------------------+
| Saturday 01 January 0000 |
+--------------------------+
1 row in set (0.00 sec)

mysql> select str_to_date("2003-01-02 10:11:12.0012", "%Y-%m-%d %H:%i:%S.%f") as f1,
    -> str_to_date("2003-01-02 10:11:12.0012", "%Y-%m-%d %H:%i:%S") as f2,
    -> str_to_date("2003-01-02", "%Y-%m-%d") as f3,
    -> str_to_date("02 10:11:12", "%d %H:%i:%S.%f") as f4,
    -> str_to_date("02 10:11:12", "%d %H:%i:%S") as f5,
    -> str_to_date("02 10", "%d %f") as f6;
+----------------------------+---------------------+------------+-----------------+----------+-----------------+
| f1                         | f2                  | f3         | f4              | f5       | f6              |
+----------------------------+---------------------+------------+-----------------+----------+-----------------+
| 2003-01-02 10:11:12.001200 | 2003-01-02 10:11:12 | 2003-01-02 | 58:11:12.000000 | 58:11:12 | 48:00:00.100000 |
+----------------------------+---------------------+------------+-----------------+----------+-----------------+
1 row in set, 1 warning (0.02 sec)

mysql> select str_to_date("2003-....01ABCD-02 10:11:12.0012", "%Y-%.%m%@-%d %H:%i:%S.%f") as a;
+---+
| a |
+---+
| NULL |
+---+
1 row in set, 1 warning (0.00 sec)

4. What is your TiDB version? (Required)

mysql> SELECT tidb_version();
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tidb_version()                                                                                                                                                                                                                                                                                                              |
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Release Version: v4.0.0-beta.2-2047-g0aa476034
Edition: Community
Git Commit Hash: 0aa476034ae8a69040ab2b4fe455114ba0e21695
Git Branch: master
UTC Build Time: 2021-01-26 02:15:59
GoVersion: go1.15.6
Race Enabled: false
TiKV Min Version: v3.0.0-60965b006877ca7234adaced7890d7b029ed1306
Check Table Before Drop: false |
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

[guo-shaoge]

Looks like it's a bug of MySQL.

result of PostgreSQl-8.4 is same with TiDB. 6 means Saturday. doc:

test=# select to_char(to_date('0000-01-01', 'YYYY-MM-DD'), '%ID');
 to_char
---------
 %6
(1 row)

We can also write a Go program to verify. The result is Saturday.

package main

import (
  "fmt"
  "time"
)

func main() {
  // means 0000-01-01 00:00:00.000000
  year, month, day, hour, minute, second, microsecond := 0, 1, 1, 0, 0, 0, 0
  t := time.Date(year, time.Month(month), day, hour, minute, second, microsecond * 1000, time.Local)
  fmt.Println(t.Weekday())
}

MySQL and PostgreSQL both use proleptic Gregorian calendar, which is required by standard SQL.

Not sure for now why MySQL's result is Sunday.

[guo-shaoge]

According to wikipedia, 1 BC starts on Saturday.

Year zero exists in ISO8601 where it coincides with the Gregorian year 1 BC(here)

So i believe it's MySQL's bug. bug report.

PS: str_to_date doesn't support %./%#/%@, need to fix.

[ti-srebot]

Please edit this comment or add a new comment to complete the following information

Not a bug

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Bug

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1. Root Cause Analysis (RCA) (optional)

2. Symptom (optional)

3. All Trigger Conditions (optional)

4. Workaround (optional)

5. Affected versions

[v2.0.0:v2.0.11], [v2.1.0:v2.1.19],[v3.0.0:v3.0.20],[v4.0.0:v4.0.10],[v5.0.0-rc]

6. Fixed versions

master

[ti-srebot]

( AffectedVersions ) fields are empty.
The values in ( AffectedVersions ) fields are incorrect.