Correctly handle mysql timestamp() and datetime() types

[Sevenannn]

This PR includes the changes to correctly handle MySQL timestamp() and datetime() types when converting to arrow types.

• MySQL timestamp(1-6) and timestamp() are all MYSQL_TYPE_TIMESTAMP
• MySQL datetime(1-6) and datetime() are all MYSQL_TYPE_DATETIME
• Use arrow TimestampMicrosecond type for mapping MYSQL_TYPE_TIMESTAMP and MYSQL_TYPE_DATETIME types, to handle up to microsecond precision for timestamp & datetime types
• Simplify the logic for convert MYSQL_TYPE_TIMESTAMP and MYSQL_TYPE_DATETIME values to arrow TimestampMicrosecond value

[hozan23]

Thanks @Sevenannn, nice work.

I wonder if we could add some tests here. Just to cover all ranging precision from 0-6 with the TIMESTAMP type.

A DATETIME or TIMESTAMP value can include a trailing fractional seconds part in up to microseconds (6 digits) precision. In particular, any fractional part in a value inserted into a DATETIME or TIMESTAMP column is stored rather than discarded.

https://dev.mysql.com/doc/refman/8.4/en/datetime.html

[Sevenannn]

Thanks for the feedback! @hozan23

I added tests for MySQL TIMESTAMP and DATETIME types, and they are now running as part of the PR test.

[hozan23]

@phillipleblanc any reason not to merge this into the main branch?

[phillipleblanc]

It should be merged it into main. Once we (Spice AI) migrate to main from our spiceai branch (TBD), it will eventually be merged in. If you want to bring it in faster, I'm happy to review the PR.