Date and Time Data Types¶
Of the SQL date and time types, Drizzle supports:
Date/Time Types
| Data Type | Lowest Value (or NULL) | Maximum Value | Description | Storage Size | Resolution |
|---|---|---|---|---|---|
| TIMESTAMP | ‘0001-01-01 00:00:00’ | ‘9999-12-31 23:59:59’ | both date and time | 4 bytes | 1 second |
| TIMESTAMP(6) | ‘0001-01-01 00:00:00.000000’ | ‘9999-12-31 23:59:59.999999’ | both date and time | 8 bytes | 1 microsecond |
| DATE | ‘0001-01-01’ | ‘9999-12-31’ | dates only | 4 bytes | 1 day |
| TIME | ‘00:00:00’ | ‘23:59:59’ | time of day | 4 bytes | 1 second |
| DATETIME | ‘0001-01-01 00:00:00’ | ‘9999-12-31 23:59:59’ | both date and time | 4 bytes | 1 second |
TIMESTAMP and TIMESTAMP(6)¶
The regular TIMESTAMP data type does not store fractional seconds, and uses 4 bytes of storage.
To create a TIMESTAMP column that uses microseconds you simply need to specify TIMESTAMP(6) in your table definition. The (6) stands for microsecond granularity (since a microsecond is one millionth of a second). This means that fractional seconds are stored and returned with the field, and it uses 4 more bytes of storage than TIMESTAMP.
For example:
CREATE TABLE `t1` (
`a` INT DEFAULT NULL,
`b` TIMESTAMP(6) NULL DEFAULT NULL
) ENGINE=InnoDB
You can then use the following (but note that ON DEFAULT/UPDATE CURRENT_TIMESTAMP works with microseconds as well):
insert into t1 values (1, '2010-01-10 07:32:43.234567');
The new table now looks like this:
| a | b |
|---|---|
| 1 | 2010-01-10 07:32:43.234567 |
DATE¶
In Drizzle, valid date inputs begin at 0001-01-01 rather than 0000-00-00, which is not a valid date (there was no year 1, there is no month zero and there is no day zero).
TIME¶
Drizzle’s TIME data type has a range of 00:00:00 - 23:59:59, while MySQL’s TIME data type has a range of -838:59:59 - 838:59:59.
This brings Drizzle closer to the SQL standard. Negative time is not meant to be supported.
To prevent data loss to this type when converting from MySQL -> Drizzle, the conversion process changes TIME to an INT of the number of seconds. For example, 00:00:00 becomes 0, 01:00:00 becomes 3600, and -01:00:00 becomes -3600.
More information on this can be found in the MySQL Migration Using drizzledump section of this documentation.
DATETIME¶
DATETIME defines a date that is combined with a time of day, based on 24-hour time. Unlike TIMESTAMP in that it does not support microseconds.
