feat(datatype): datatype timestamp with precision

[Veeupup]

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Summary

• alias datatype timestamp alias to datetime and timestamp(n) can have precision like datetime(n)
• default timestamp precision is 6.

Changelog

• New Feature

Related Issues

Fixes #4994

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Name	Status	Preview	Updated
databend	⬜️ Ignored (Inspect)		Apr 22, 2022 at 3:59AM (UTC)

[mergify]

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[BohuTANG]

Cool.
It would be great to add some datetime cast or bound check in the file(it's empty now):
https://github.com/datafuselabs/databend/blob/main/tests/suites/0_stateless/11_data_type/11_0001_data_type_date_time.sql

[Veeupup]

Cool.
It would be great to add some datetime cast or bound check in the file(it's empty now):

https://github.com/datafuselabs/databend/blob/main/tests/suites/0_stateless/11_data_type/[11_0001_data_type_date_time.sql
]

(#4874)
Maybe this can be fixed with this issue

[BohuTANG]

Cool.
It would be great to add some datetime cast or bound check in the file(it's empty now):

[https://github.com/datafuselabs/databend/blob/main/tests/suites/0_stateless/11_data_type/11_0001_data_type_date_time.sql ]

(#4874) Maybe this can be fixed with this issue

Ok, let's merge :D

[b41sh]

@Veeupup The default precision of datetime has changed, so the documentation also needs to be modified.
https://github.com/datafuselabs/databend/blob/main/docs/doc/30-reference/10-data-types/20-data-type-time-date-types.md

[BohuTANG]

@Veeupup The default precision of datetime has changed, so the documentation also needs to be modified. https://github.com/datafuselabs/databend/blob/main/docs/doc/30-reference/10-data-types/20-data-type-time-date-types.md

I will do that, not only the datatype also some examples.

[BohuTANG]

DATETIME should be an alias for TIMESTAMP, now databend TIMESTAMP is an alias for DATETIME.

mysql> create table t2(a timestamp);
Query OK, 0 rows affected (0.07 sec)
Read 0 rows, 0 B in 0.019 sec., 0 rows/sec., 0 B/sec.

mysql> desc t2;
+-------+-------------+------+---------+-------+
| Field | Type        | Null | Default | Extra |
+-------+-------------+------+---------+-------+
| a     | DATETIME(6) | NO   | 0       |       |
+-------+-------------+------+---------+-------+

See:
https://docs.snowflake.com/en/sql-reference/data-types-datetime.html#datetime
https://duckdb.org/docs/sql/data_types/timestamp
https://www.cockroachlabs.com/docs/stable/timestamp.html (CRDB has no DATETIME type)

cc @Veeupup @sundy-li