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- MySQL 5.7 Manual
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- MySQL 5.5 Manual
- MySQL 5.1 Manual
- MySQL 5.0 Manual
- MySQL 3.23/4.0/4.1 Manual
- Table of Contents
- 10.3 Date and Time Types
- 10.3.1 The DATE, DATETIME, and TIMESTAMP Types
- 10.3.2 The TIME Type
- 10.3.3 The YEAR Type
- 10.3.4 Fractional Seconds in Time Values
- 10.3.5 Conversion Between Date and Time Types
- 10.3.6 Two-Digit Years in Dates
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The DATE,
DATETIME, and
TIMESTAMP types are related. This
section describes their characteristics, how they are similar,
and how they differ.
The DATE type is used for values
with a date part but no time part. MySQL 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. MySQL 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'.
For the DATE and
DATETIME range descriptions,
“supported” means that although earlier values
might work, there is no guarantee.
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. Its properties are
described in more detail in Section 10.3.1.2, “TIMESTAMP Properties as of MySQL 4.1”.
MySQL recognizes DATE,
DATETIME, and
TIMESTAMP values in several
formats, described in Section 8.1.3, “Date and Time Literals”.
A DATETIME or
TIMESTAMP value can include a
trailing fractional seconds part in up to microseconds (6
digits) precision. Although this fractional part is recognized,
it is discarded from values stored into
DATETIME or
TIMESTAMP columns. For
information about fractional seconds support in MySQL, see
Section 10.3.4, “Fractional Seconds in Time Values”.
Illegal DATE,
DATETIME, or
TIMESTAMP values are converted to
the “zero” value of the appropriate type
('0000-00-00', '0000-00-00
00:00:00', or 00000000000000).
Be aware of certain problems when specifying date values:
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 MySQL server performs only basic checking on the validity of a date: The ranges for year, month, and day are 1000 to 9999, 00 to 12, and 00 to 31, respectively. Any date containing parts not within these ranges is subject to conversion to
'0000-00-00'. Please note that this still permits you to store invalid dates such as'2002-04-31'. To ensure that a date is valid, perform a check in your application.Dates containing two-digit year values are ambiguous because the century is unknown. MySQL 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.
User Comments
You can automatically convert an invalid date to the valid equivalent like this:
SELECT '2008-02-31' + INTERVAL 0 DAY;
# 2008-03-02
This lets you avoid storing invalid dates without bothering the user and without having to manually program a fix into your app. I suppose in >=5.0.2, you'd have to enable ALLOW_INVALID_DATES to avoid having it converted to '0000-00-00'. This also works with DATETIMEs.
In addition to Linus Rachlis,
if you add 0 month to an invalid date, you could get last day of the month, for example
SELECT '2008-02-31' + INTERVAL 0 MONTH;
# 2008-02-29
It works as
SELECT LAST_DAY('2008-02-31');
# 2008-02-29
even we can add a trigger to check a valid date so that it atomatically changes to correct date
A possible problem that can happen with date_format and ORDER/GROUP BY is explained at http://www.geeksww.com/tutorials/database_management_systems/mysql/tips_and_tricks/mysql_dateformat_function_and_order_by.php
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