i keep getting this error when trying to set up a default value for a date field:
Invalid default value for 'created'
ALTER TABLE artwork CHANGE COLUMN created created TIMESTAMP NOT NULL DEFAULT '1954-09-18 00:00:00' AFTER updated;
I've tried every year and i notice that prior to 1970, mysql rejects the date. I mean it's not a big problem, i really don't need the default date to be 1954, if i want that date it is mostly for symbolic reasons.
Assuming that there is no direct solution for my issue, then my question is: why is it that mysql rejects default dates prior to 1970 ?
Thanks
I'm not familiar with mysql, but Unix timestamps (which are widely used) are a count of seconds since 1970-01-01 00:00:00 GMT. If mysql uses that format internally, it probably doesn't like a timestamp with a negative value.
EDIT:
http://dev.mysql.com/doc/refman/5.0/en/date-and-time-type-overview.html :
TIMESTAMP
A timestamp. The range is '1970-01-01 00:00:01' UTC to '2038-01-19
03:14:07' UTC. TIMESTAMP values are stored as the number of seconds
since the epoch ('1970-01-01 00:00:00' UTC). A TIMESTAMP cannot
represent the value '1970-01-01 00:00:00' because that is equivalent
to 0 seconds from the epoch and the value 0 is reserved for
representing '0000-00-00 00:00:00', the “zero” TIMESTAMP value.
MySQL's TIMESTAMP type is a counter representing Unix time. That's the number of seconds since the start of January 1, 1970. Why it is signed (maximum date is in 2038 -- half the time that would would be allowable if it were unsigned) and doesn't allow dates outside the 1970-2038 range is beyond me. See also the MySQL documentation on this column type.
The DATETIME column type uses twice the space (8 bytes), but the supported range there is '1000-01-01 00:00:00' to '9999-12-31 23:59:59'.
Related
I'm trying to insert a date time value e.g. 1970-01-01 00:00:01 in a column of timestamp datatype in MySQL table but getting following error:
#1292 - Incorrect datetime value: '1970-01-01 00:00:01' for column 'order_date' at row 1
But according to MySQL docs - The TIMESTAMP value has a range from '1970-01-01 00:00:01' UTC to '2038-01-19 03:14:07' UTC.
So if the range value starts from 1970-01-01 00:00:01 UTC then why this value can't be inserted in the table? Is there something to do with UTC? What will be the minimum date time value for timestamp that can be inserted without any issue?
Timestamp columns store a utc value and start at 1970-01-01 00:00:01, but whenever you read or write them, they convert to/from your session timezone. This makes them something of a nightmare to work with if you are actually intending to only use UTC.
Just use a datetime type if you ever are trying to set particular times that come from your client. If you must use timestamp and want to set a particular UTC time, first do:
set session time_zone='+00:00';
But note that any client that doesn't do that may see a different time. Even if you set your server timezone to UTC, so that sessions default to UTC, some client libraries "helpfully" set the session timezone when they connect.
select FROM_UNIXTIME(32154654321);
Output:Null
Expected Result: Tuesday, December 9, 2988 1:55:21 PM GMT+05:30
This is why: https://dev.mysql.com/doc/refman/5.5/en/datetime.html
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.
This is the Year-2038 problem. The maximum value of the TIMESTAMP datatype is 2038-01-19 03:14:07, so you can't get the expected result.
MySQL 5.5: 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.
source: https://dev.mysql.com/doc/refman/5.5/en/datetime.html
MySQL 5.6+: [...] and the range for TIMESTAMP values is '1970-01-01 00:00:01.000000' to '2038-01-19 03:14:07.999999'.
source: https://dev.mysql.com/doc/refman/5.7/en/datetime.html
You can find a very good answer on stackoverflow with some more details about this problem.
You can use PHP instead of MySQL to convert the timestamp (not stored in a TIMESTAMP column) to a readable datetime, with the following code:
$timestamp = 32154654321;
$format = 'Y-m-d H:i:s';
$date = new DateTime();
$date->setTimestamp($timestamp);
echo $date->format($format);
demo: http://ideone.com/DsYUOQ
You cannot input like 32154654321
Timestamps in mysql have a maximum value of 2147483647, equivalent
to 2038-01-19 05:14:07. This is due to the underlying 32-bit
limitation. Using the function on a timestamp beyond this will result
in NULL being returned. Use DATETIME as a storage type if you require
dates beyond this.
UPDATE test SET add_time = '2017-04-29' WHERE id = 1;
The type of 'add_time' is timestmap,the above statement will be inserted '2017-04-29 15:00:00',my question is why it is not '2017-04-29 00:00:00'.It may be related to the time zone of mysql?
In MySQL 5 and above, TIMESTAMP values are converted from the current time zone to UTC for storage, and converted back from UTC to the current time zone for retrieval. (This occurs only for the TIMESTAMP data type, and not 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 described in MySQL Server Time Zone Support.
2017-04-29 15:00:00 means that its a time of 3 PM, 29th April, 2017. Timestamp saves date and time as well. And that time is because of the time zone.
However if you need to select datepart only, you can do the following:
SELECT date(ColumnName) from tablename
The above will get only the date part only.
The DATETIME type is used when you need values that contain both date
and time information. 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'.
...
The TIMESTAMP data type has a range of '1970-01-01 00:00:01' UTC to
'2038-01-09 03:14:07' UTC. It has varying properties, depending on the
MySQL version and the SQL mode the server is running in.
For your situation, I will suggest you to use datetime instead of timestamp
I need to store both time and date in the mysql. So I used of NOW() function for that. But I don't know what should I use for type column im phpmyadmin. It should be noted that NOW() returns both time and date like this:
2014-11-11 12:45:34
Here is a solution, I can use of a separator for separating date and time (2014-11-11 and 12:45:34) and then store them in the DATE type and TIME type individually. Or I can use of VARCHAR type for storing both of them in one column. But I think these ways are not standard. what is standard type for storing both date and time ?
Here is my query: (also I don't know why NOW() function does not works)
INSERT INTO table (timedate) VALUES (NOW())
DATE: It 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.
DATETIME: It 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.
TIMESTAMP: It is also used for values that contain both date and time parts, and includes the time zone. TIMESTAMP has a range of 1970-01-01 00:00:01 UTC to 2038-01-19 03:14:07 UTC.
TIME: Its values are in HH:MM:SS format (or HHH:MM:SS format for large hours values). TIME values may range from -838:59:59 to 838:59:59. The hours part may be so large because the TIME type can be used not only to represent a time of day (which must be less than 24 hours), but also elapsed time or a time interval between two events (which may be much greater than 24 hours, or even negative).
I have a slightly different perspective on the difference between a DATETIME and a TIMESTAMP. A DATETIME stores a literal value of a date and time with no reference to any particular timezone. So, I can set a DATETIME column to a value such as '2019-01-16 12:15:00' to indicate precisely when my last birthday occurred. Was this Eastern Standard Time? Pacific Standard Time? Who knows? Where the current session time zone of the server comes into play occurs when you set a DATETIME column to some value such as NOW(). The value stored will be the current date and time using the current session time zone in effect. But once a DATETIME column has been set, it will display the same regardless of what the current session time zone is.
A TIMESTAMP column on the other hand takes the '2019-01-16 12:15:00' value you are setting into it and interprets it in the current session time zone to compute an internal representation relative to 1/1/1970 00:00:00 UTC. When the column is displayed, it will be converted back for display based on whatever the current session time zone is. It's a useful fiction to think of a TIMESTAMP as taking the value you are setting and converting it from the current session time zone to UTC for storing and then converting it back to the current session time zone for displaying.
If my server is in San Francisco but I am running an event in New York that starts on 9/1/1029 at 20:00, I would use a TIMESTAMP column for holding the start time, set the session time zone to 'America/New York' and set the start time to '2009-09-01 20:00:00'. If I want to know whether the event has occurred or not, regardless of the current session time zone setting I can compare the start time with NOW(). Of course, for displaying in a meaningful way to a perspective customer, I would need to set the correct session time zone. If I did not need to do time comparisons, then I would probably be better off just using a DATETIME column, which will display correctly (with an implied EST time zone) regardless of what the current session time zone is.
TIMESTAMP LIMITATION
The TIMESTAMP type has a range of '1970-01-01 00:00:01' UTC to '2038-01-19 03:14:07' UTC and so it may not usable for your particular application. In that case you will have to use a DATETIME type. You will, of course, always have to be concerned that the current session time zone is set properly whenever you are using this type with date functions such as NOW().
Saty described the differences between them. For your practice, you can use datetime in order to keep the output of NOW().
For example:
CREATE TABLE Orders
(
OrderId int NOT NULL,
ProductName varchar(50) NOT NULL,
OrderDate datetime NOT NULL DEFAULT NOW(),
PRIMARY KEY (OrderId)
)
You can read more at w3schools.
In shorter explanation
DATE: The DATE stores a date value in the form YYYY-MM-DD (year-month-day). It does not store time.
TIME: The TIME stores a time value in the form HH:MM:SS (hours-minutes-seconds). It does not store the date.
DATETIME: The DATETIME stores a date and time value in the form YYYY-MM-DD HH:MM:SS. It stores both the date and time.
TIMESTAMP: The TIMESTAMP is similar to the DATETIME, but includes a timezone. (Example of values YYYY-MM-DD HH:MM:SS +HH:MM, YYYY-MM-DD HH:MM:SS -HH:MM. +HH:MM and -HH:MM indicate the time zone from UTC (Coordinated Universal Time).
I posted a question as to why the following query filed to search the date.
SELECT * FROM Stuff Where Sell_by <= 2013-07-04;
I was given the newbie answer of "You are searching for the result of the equation 2013-07-04"
That makes perfect sense to me. So I use the following and it come out just fine:
SELECT * FROM Stuff Where Sell_by <= '2013-07-04';
But it raises another question: If 2013 minus 7 minus 4 is 2002. (I assume that is what MySQL is saying)
When is day Zero? (And what is there any significance to that date?)
The answer depends on what Sell_by is. Your basic types to store dates are DATE, DATETIME, and TIMESTAMP. From the MySQL manual:
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'.
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.
It doesn't really make much sense to call January 1st, 1000 "day zero", though, at least in my opinion. It happens to be the earliest day representable by DATE and DATETIME, but it has a well-known value that's different from zero, namely the first day of the year 1000.
Okay, by that logic you could argue that 1970-01-01 doesn't have the right to call itself zero, either. But this starting date for TIMESTAMP is chosen as the beginning point of Unix time. And since that time format is defined as "let's count the seconds that happend since the beginning of 1970" (...ish), it really does start with a zero.
Long story short, there is no "day zero", only things that could be interpreted as zero, depending how you look at them.
http://dev.mysql.com/doc/refman/5.6/en/datetime.html says:
MySQL retrieves and displays DATE values in 'YYYY-MM-DD' format. The supported range is '1000-01-01' to '9999-12-31'.
Later:
Invalid 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').
Read the page for more details.