A fraction part of datetime/timestamp value is truncated

[uki00a]

Summary

• The datetime/timestamp value can include a trailing fractional seconds part. (like this: YYYY-MM-DD hh:mm:ss[.fraction])
• deno_mysql currently truncates a fraction part of these types.

Steps to reproduce

import { Client, Connection } from "https://deno.land/x/mysql@2.2.0/mod.ts";
import { assertEquals } from "https://deno.land/std@0.60.0/testing/asserts.ts";

const client = await new Client().connect({
  hostname: "localhost",
  port: 3306,
  username: "test",
  db: "test",
  password: "test",
});

await client.query(`DROP TABLE IF EXISTS test`);
await client.query(`CREATE TABLE test (
  id int(11) NOT NULL AUTO_INCREMENT,
  datetime datetime(6) NOT NULL,
  PRIMARY KEY (id)
) ENGINE=MEMORY DEFAULT CHARSET=utf8mb4`);

const datetime = new Date();
await client.execute(`
  INSERT INTO test (datetime)
  VALUES (?)`, [datetime]);

const expected = datetime;
const [{ datetime: actual }] = await client.query(`SELECT datetime FROM test`);
assertEquals(expected.toISOString(), actual.toISOString()); // See https://github.com/denoland/deno/issues/6643 for why not simply using `assertEquals(actual, expected)`.

Expected behavior:

The above code shouldn't fail.

Actual behavior:

The above code fails with the fowlloing logs:

INFO connecting localhost:3306
INFO connected to localhost
error: Uncaught AssertionError: Values are not equal:


    [Diff] Actual / Expected


-   "2020-07-07T19:32:24.464Z"
+   "2020-07-07T19:32:24.000Z"

  throw new AssertionError(message);
        ^
    at assertEquals (asserts.ts:183:9)
    at file:///home/uki00a/work/test.ts:22:1

Environment

• deno v1.1.3
• deno_mysql v2.2.0
• MySQL v5.7

Ref

https://dev.mysql.com/doc/refman/5.6/en/datetime.html