The DATE, DATETIME, and TIMESTAMP Types
The DATE, DATETIME, and TIMESTAMP types are related. This section describes their characteristics, how they are similar, and how they differ. MariaDB recognizes DATE, DATETIME, and TIMESTAMP values in several formats, described in , "Date and Time Literals". For the DATE and DATETIME range descriptions, "supported" means that although earlier values might work, there is no guarantee.
The DATE type is used for values with a date part but no time part. MariaDB retrieves and displays DATE values in 'YYYY-MM-DD' format. The supported range is '1000-01-01' to '9999-12-31'.
The DATETIME type is used for values that contain both date and time parts. MariaDB retrieves and displays DATETIME values in 'YYYY-MM-DD HH:MM:SS' format. The supported range is '1000-01-01 00:00:00' to '9999-12-31 23:59:59'.
The TIMESTAMP data type is used for values that contain both date and time parts. TIMESTAMP has a range of '1970-01-01 00:00:01' UTC to '2038-01-19 03:14:07' UTC.
A DATETIME or TIMESTAMP value can include a trailing fractional seconds part in up to microseconds (6 digits) precision. In particular, as of MariaDB 5.6.4, any fractional part in a value inserted into a DATETIME or TIMESTAMP column is stored rather than discarded. With the fractional part included, the format for these values is 'YYYY-MM-DD HH:MM:SS[.fraction]', the range for DATETIME values is '1000-01-01 00:00:00.000000' to '9999-12-31 23:59:59.999999', and the range for TIMESTAMP values is '1970-01-01 00:00:01.000000' to '2038-01-19 03:14:07.999999'. For information about fractional seconds support in MySQL, see , "Fractional Seconds in Time Values".
The TIMESTAMP and (as of MariaDB 5.6.5) DATETIME data types offer automatic initialization and updating to the current date and time. For more information, see , "Automatic Initialization and Updating for TIMESTAMP and DATETIME".
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. If you store a TIMESTAMP value, and then change the time zone and retrieve the value, the retrieved value is different from the value you stored. This occurs because the same time zone was not used for conversion in both directions. The current time zone is available as the value of the time_zone system variable. For more information, see , "MySQL Server Time Zone Support".
Illegal DATE, DATETIME, or TIMESTAMP values are converted to the "zero" value of the appropriate type ('0000-00-00' or '0000-00-00 00:00:00').
Be aware of certain properties of date value interpretation in MySQL:
- MySQL permits a "relaxed" format for values specified as strings, in which any punctuation character may be used as the delimiter between date parts or time parts. In some cases, this syntax can be deceiving. For example, a value such as
'10:11:12'might look like a time value because of the ":" delimiter, but is interpreted as the year'2010-11-12'if used in a date context. The value'10:45:15'is converted to'0000-00-00'because'45'is not a legal month. - The server requires that month and day values be legal, and not merely in the range 1 to 12 and 1 to 31, respectively. With strict mode disabled, invalid dates such as
'2004-04-31'are converted to'0000-00-00'and a warning is generated. With strict mode enabled, invalid dates generate an error. To permit such dates, enableALLOW_INVALID_DATES. See , "Server SQL Modes", for more information. - MySQL does not accept
TIMESTAMPvalues that include a zero in the day or month column or values that are not a valid date. The sole exception to this rule is the special "zero" value'0000-00-00 00:00:00'. - Dates containing two-digit year values are ambiguous because the century is unknown. MariaDB interprets two-digit year values using these rules:
- Year values in the range
00-69are converted to2000-2069. - Year values in the range
70-99are converted to1970-1999.
See also , "Two-Digit Years in Dates".
- Year values in the range
The MariaDB server can be run with the MAXDB SQL mode enabled. In this case, TIMESTAMP is identical with DATETIME. If this mode is enabled at the time that a table is created, TIMESTAMP columns are created as DATETIME columns. As a result, such columns use DATETIME display format, have the same range of values, and there is no automatic initialization or updating to the current date and time. See , "Server SQL Modes".