Date mismatch in database when queried by node script - mysql

Question

I have a node script that creates a date object, converts it into a string, console logs date and date as string and then inserts date string into a sql database fields of type DATE, DATETIME and TIMESTAMP. The database is on Windows 10 in XAMPP, local time is 2PM.
(async () => {
const fs = require("fs");
const mysql = require('mysql2/promise');
let date = new Date();
let dateString = date.getFullYear() + "-" + (date.getMonth() + 1) + "-" + date.getDate();
console.log("date: ", date);
console.log("datestring: ", dateString);
const connection = await mysql.createConnection(JSON.parse(fs.readFileSync("../test/databaseLogin.json")));
await connection.execute("INSERT INTO dates VALUES (?, ?, ?, ?)", [1, dateString, dateString, dateString]);
const selectResults = await connection.execute("SELECT * FROM `dates` WHERE mainKey = ?", [1]);
console.log("DB field of type DATE: ", selectResults[0][0].date);
console.log("DB field of type DATETIME: ", selectResults[0][0].datetime);
console.log("DB field of type TIMESTAMP: ", selectResults[0][0].timestamp);
connection.close();
})();
If I query the database from node process with mysql2 npm I get different result that says 24th instead of 25th.
Complete console output:
date: 2019-12-25T13:19:01.204Z
datestring: 2019-12-25
DB field of type DATE: 2019-12-24T23:00:00.000Z
DB field of type DATETIME: 2019-12-24T23:00:00.000Z
DB field of type TIMESTAMP: 2019-12-24T23:00:00.000Z
I don’t understand why there is a difference. Maybe some sort of localization issue? But the date was created in same locale as it was read.
Databse representation of data:
MariaDB [test]> SELECT * FROM dates;
+---------+------------+---------------------+---------------------+
| mainKey | date | datetime | timestamp |
+---------+------------+---------------------+---------------------+
| 1 | 2019-12-25 | 2019-12-25 00:00:00 | 2019-12-25 00:00:00 |
+---------+------------+---------------------+---------------------+
MariaDB [test]> describe dates;
+-----------+-----------+------+-----+-------------------+-----------------------------+
| Field | Type | Null | Key | Default | Extra |
+-----------+-----------+------+-----+-------------------+-----------------------------+
| mainKey | int(11) | NO | PRI | NULL | |
| date | date | NO | PRI | NULL | |
| datetime | datetime | NO | | NULL | |
| timestamp | timestamp | NO | | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
+-----------+-----------+------+-----+-------------------+-----------------------------+
MySQL converts TIMESTAMP values from the current time zone to UTC for storage, and back from UTC to the current time zone for retrieval. (This does not occur for other types such as DATETIME.) By default, the current time zone for each connection is the server's time. The time zone can be set on a per-connection basis. As long as the time zone setting remains constant, you get back the same value you store.
I think mysql2 npm does not support time zone config per connection.

Answer 1

I found the answer when visiting issues page of the mysql2 npm module.
To get the date string "as is" back form the database, I had to add the following connection settings: dateStrings: true. Full connection object looks now like so:
const connection = await mysql.createConnection({
host: 'localhost',
user: 'root',
password: 'pass',
database: 'test',
dateStrings: true
});
Console output:
date: 2019-12-25T20:38:09.522Z
datestring: 2019-12-25
DB field of type DATE: 2019-12-25
DB field of type DATETIME: 2019-12-25
DB field of type TIMESTAMP: 2019-12-25