I am trying to insert the date below into my TIMESTAMP column but it's unexpectedly signaled as incorrect format by mysql :
INSERT INTO `assets`( `updated_at`) VALUES ('2022-03-27 02:12:31.217573')
If i add or substract one day or one hour then the date is executed without error.
I going crazy ^^
Thx for your help
mysql version : 5.7.36
timestamp columns are weird. They effectively store a utc time, but on input and output convert to the timezone of the connection. Presumably you are using a timezone that has daylight savings where the second after 2022-03-27 01:59:59 is 2022-03-27 03:00:00, so your entered time is invalid.
If you intend to be storing times that are already in UTC (which you should!) you need to set your timezone appropriately. See https://dev.mysql.com/doc/refman/5.7/en/time-zone-support.html. But be aware that then all previously entered times will appear to change.
I much prefer to use datetime columns which will store and show exactly the data entered, though they have their own quirks.
Related
I am using DATETIME field to store my dates in MySQL. Without any timezone specified directly (there is just a datetime column)
But when timezone was changed on server MySQL updated all datetime columns according to new timezone.
Actually switching to EDT was the reason.
I don't need to recalculate my dates automatically - just want to store specific dates in it.
So even if tz changed manually to UTC from EST date should be same (from characters POV) if it was 2016-01-01 18:55 it should be same in any new tz..
I did not run any scripts\queries to update dates.
So it was performed either by MySQL itself or by server.
Need advice what I need to check to find and disable such feature.
Make sure you are using DATETIME and not TIMESTAMP
[From the MySQL documentation][1]:
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.)
You should also review this post (Duplicate):
Will changing a MySQL timezone change values of DateTime fields in a database?
I am sorry for the mess I brought
Just extended my query to grab some old dates - and it looks unchanged
So error defenetly in my code..
Anyway - thanks for your help
So ... I inserted an entry into a table with time stamps. The entry got inserted perfectly.
But the time stamp that got inserted was :
'2015-06-22 10:32:47'
I checked the time on the server:
Tue Jun 23 01:35:41 IST 2015
And inside mysql :
select now();
2015-06-23 01:33:57
So I check the time in irb.
time = Time.now
=> 2015-06-23 01:36:41 +0530
time.zone
=> "IST"
The time zone is right .. but I dont know where is it picking up the time from? I cant figure out where is it picking up 10:32 from ? and how do I fix it ?
Appreciate all your help.
Rails by design converts a datetime into UTC before inserting the value into the database.
This is because, in general, it's not possible to easily represent timezones in the database. Moreover, this approach guarantees the date will be consistent and/or easy to query in the following cases:
if the server time zone changes or you change server with a different timezone
if you want to query the date using a different timezone
if you want to format the date with different time zones depending on the user or other configs
You can customize the default timezone for the app, so that Rails will properly compute the correct difference to UTC when the value is stored into the database. However, you cannot change this behavior: times will always be converted into UTC before being stored in the database.
Generally speaking, if you properly use the Rails date transformation helpers, this shouldn't cause any issue.
For instance, if you want to query all the records where the time is past, the following query
Record.where('some_date < ?', Time.current)
will properly convert Time.current from your app timezone into UTC, and query the database accordingly.
I run the following MySQL query:
select unix_timestamp('2011-03-13 02:00:13'), unix_timestamp('2011-03-13 02:20:41'), unix_timestamp('2011-03-13 02:40:10');
And get the following odd result:
1300003200, 1300003200, 1300003200
I think there's some kind of daylight savings time going on here, though it still seems odd that all the values are magically the same.
I'd appreciate suggestions of how to prevent MySQL from doing daylight savings time things here, as well as some explanation as to why all the results are the same.
MySQL's behavior is correct, if your server's time zone "CDT" observes DST and you haven't set your session time zone to something different.
The UNIX_TIMESTAMP() function uses your session's time zone to interepret the value you give it.
The server interprets date as a value in the current time zone and converts it to an internal value in UTC.
...
Note: If you use UNIX_TIMESTAMP() and FROM_UNIXTIME() to convert between TIMESTAMP values and Unix timestamp values, the conversion is lossy because the mapping is not one-to-one in both directions. For example, due to conventions for local time zone changes, it is possible for two UNIX_TIMESTAMP() to map two TIMESTAMP values to the same Unix timestamp value. FROM_UNIXTIME() will map that value back to only one of the original TIMESTAMP values.
— http://dev.mysql.com/doc/refman/5.5/en/date-and-time-functions.html#function_unix-timestamp
The timestamps in question did not exist in your time zone, so the server is giving you the most accurate possible answer... it's the time in UTC that the clock moved forward to, when the time moved forward, less than an hour prior to your datetime literals, which represent "times that never existed on that day" in your time zone.
If those timestamps are intended to be times in your local time zone, then the answer is that those are invalid values, since that time never happened where you are. On the other hand, if those timestamps are actually assumed to already be in UTC, then you're not getting the correct answer from UNIX_TIMESTAMP() on any query, because the time is being converted "from" a time zone it isn't actually expressed in.
If you SET ##TIME_ZONE = 'UTC'; and repeat the queries, you'll see what I mean, since UTC has no DST. This statment only sets your session's time zone, not the whole server.
If running SET ##TIME_ZONE = 'UTC'; gives you an error message such as ERROR 1298 (HY000): Unknown or incorrect time zone: 'UTC', it is likely that you have not populated MySQL with timezone information. As described here you can load this information by using the command:
mysql_tzinfo_to_sql /usr/share/zoneinfo/ | mysql -u root mysql -p
where the path /usr/share/zoneinfo may need to be replaced with a path specific to your system.
According to mysqltutorial
The values of the MySQL TIMESTAMP columns depend on connection’s time
zone. When insert values for MySQL TIMESTAMP columns, they are
converted to Universal Coordinated Time (UTC) from connection’s time
zone. When you select the value, the server converts it back from UTC
to the connection’s time zone so you have the same value that you
inserted.
Where does it get this info. from, the time the user sets his OS to or from some other method?
Javascript also has a way to do timezones but is more involved: onlineaspect
To specify connection-specific time you need to perform
SET time_zone = TZ;
Where TZ can be either numerical offset like +11:00 or name of timezone Asia/Vladivostok (for the latter you need to import timezones description. Ask your DBA to do so)
the example there is wrong, i just tested it. it returns the previously inserted timestamp, regardless of the timezone. mysql will always insert the time you specify, without modifying it. if you need timezone adjustment, you have to tell mysql explicit to do so; otherwise all times are assumed to be "local server time".
Say I have multiple servers in multiple locations and I want to use MySQL's datetime type for the field date and I always want to have the field date have the UTC timestamp so I would execute a UTC_TIMESTAMP() when I add it to the database. Now say I want to have MySQL output the UNIX TIMESTAMP for it.
When I do this on Server A I get the string "2009-06-17 12:00:00" doing the UNIX_TIMESTAMP(STRING) on it gives me the number 1245240000 back. Which is 2009-06-17 12:00:00 in UTC time. Now I do the same thing on Server B.
I get the same string back since its the UTC string but when executing UNIX_TIMESTAMP(STRING) again I get back the wrong number back 1245232800 which is the UTC +2 time. How do I get around this? Should I do the convertion from string to timestamp on the PHP side?
G'day,
I'll ask the obvious here, did you check the date and time on both machines?
Edit: ... and the MySQL timezone was the same on both machines?
Update: Ok. The problem is in the fact that the timestamp string being passed into UNIX_TIMESTAMP is interpreted to be a value in the current timezone which is then converted back to UTC so, because you're in MEZ, two hours is subtracted to return it back to UTC so 7200 is subtracted from your timestamp when it is converted back to a Unix timestring.
Hence, the variation you see when using UNIX_TIMESTAMP() to convert is back to a Unix Epoch timestring.
BTW Shouldn't you be using a TIMESTAMP type for storing off your UTC_TIMESTAMPs instead of DATETIME type?
Update: Decoupling presentation time from stored time is definitely the way to go. You can then reuse the same data all around the world and only have to convert to and from local time when you are presenting the data to a user.
If you don't do this then you are going to have to store off the timezone when the timestamp was made and then go into all sorts of complicated permutations of having to work out if
the local timezone was in daylight saving time when it was stored,
what the difference is between the timezone at the time that the data was stored and the timezone where the data is to be presented.
Leaving it all storeed as UTC gets rid of that.
Most users won't be that happy if they have to work out the local time themselves based on the UTC time returned so systems usually convert to current local time for the user.
This is of course if the user wants the data expressed in local time which is usually the case. The only widely used system I can think of, off the top of my head, that stores and presents its data in UTC is system for air traffic control and flight plan management which are always kept in UTC (or ZULU time to be more precise).
HTH
cheers,
Have you tried doing this?
Execute this instructions together.
SET time_zone = 'UTC';
SELECT FROM_UNIXTIME(0), UNIX_TIMESTAMP('2009-06-17 12:00:00');
// 1970-01-01 00:00:00 1245240000
They only affect the client session, not the server configuration.