Using mysql, in a post table I use CURRENT_TIMESTAMP to store the date_time of publication.
Everything was ok when I was working on wampserver on local.
But I hosted my site yesterday on a server located in France, 2 hours away from the time zone of my country.
I'm using a timeago plug-in which processes the date and displays the elapsed time (there is .. sec ago, there is .. min ago, there is .. h ago, there is .. year ago) since the publication of a content.
After posting, I see "2 hours ago" when I just published 30 seconds ago.
How can I take into account the time zone of my users compared to the date and time of the server of my host?
Sample: If I post a content, 30 seconds later Me and the user who is at china or anywhere must see "30 seconds ago".
I tried that:
$d ="2020-02-28T13:09:33Z";
<time class='timeago' datetime='<?= $d ?>'> </time>
But instead of giving me "30 seconds ago", It gives me "2 hours ago".
Thank you.
I suspect you are calculating the relative time on the client side. For example, by timego plugin.
Neither MySQL, nor PHP know user's location and timezone. So, it's better to inform JS about server timezone and let it calculate the offset right.
Use ISO 8601 date time format to let timeago pligin know about server timezone. All the rest is up to JS plugin:
<?php
$ts = strtotime($row['date_time']);
?>
<time class="timeago" datetime="<?= date(DATE_ISO8601, $ts) ?>">
<?= date('Y-m-d H:i:s', $ts) ?>
</time>
<script type="text/javascript">
jQuery(function($) {
$("time.DateTime").timeago();
});
</script>
MySQL stores DATETIME without timezone information, but datetime values that are not timezone-aware are semi-useless.
So you have different options.
First option: continue to store datetime values in your current timezone, but add a second column with the proper 'offset' versus UTC, for example +1 if you are in France. Then you can perform calculation on the fly to another timezone but it is tricky because of daylight saving settings. During a certain period of the year the offset will be +1, at other times it could be +2.
So I don't recommend this approach. It's not going to scale well over time.
Other option: you can store all datetime values as UTC in your database and
then in your application you recalculate them by applying the correct offset according to your own timezone (or that of your web visitors).
This is a better option.
Whatever you do, it is important to know the timezone that applies to a given datetime value. So choose one and stick to it.
PHP has functions to handle time zone conversions, see for example: https://www.php.net/manual/en/class.datetimezone.php
Note that TIMESTAMP is limited to 1970-2038... Year 2038 problem
I am programmatically generating new form responses from rows of data in a Google Sheet (one approval workflow system generates new approval requests in a second approval workflow system). The data includes dates. My script takes the date value as a string from a cell, converts it into a native JavaScript date object, then submits this to a new form response using createResponse(). Here's the pertinent code:
var startDate = googleFormsDateStringToDate(eventDetails['Event Start Date']);
var r = item.createResponse(startDate);
For the most part, the system works robustly. Except for one intriguing problem - for any date after 29/04/2020, the date stored in the response is decremented by 1 day. Any date on or before this date works as expected, any date after is decremented by a day.
I have tried a few things.
The dates correspond to a start date and end date for an event. If the start date is before this date and the end date after, the end date will be decremented whilst the start date is recorded accurately. So I am certain the issue is directly related to whether the date I am submitting falls before or after this date.
I have tested extensively and am absolutely certain that the string-date conversion is working. If I retrieve the value of the response immediately after creating it (before the form response is even submitted), I find that it has been decremented:
var startDate = dateStringToDate(eventDetails['Event Start Date']);
Logger.log(startDate.toString()); // startDate is always accurate
var r = item.createResponse(startDate);
Logger.log(r.getResponse()); // if after 29/04/2020, will be decremented by 1 day
This tells me the issue is occurring precisely when I create the response and that it is occurring "at Google's end".
One of my suspicions is that it may be a timezone issue, but that would not explain why the issue is linked directly to this specific date. My other suspicion is that it may be to do with the fact that 2020 is a leap year, so we get 29/02/2020, and the date after which the error occurs is 29/03/2020. Perhaps somewhere behind Google's implementation of createResponse it is failing to account for the leap year?
Until I can identify the error, I plan to implement a workaround in which I will use getResponse() to check if the response date matches the intended date and correct accordingly. But I would prefer to understand what is causing the error (so I know if it is a bug requiring reporting, or simply my lack of understanding) and, if possible, find a solution.
So, specific questions: What is the source of the error? Is there a solution (rather than a workaround)?
EDIT
Whilst figuring out a workaround, I have answered my first question. In the UK, daylight savings time starts on 29/04/2020. Since the dates entered via the Google Form have no time associated with them, the time appears to be stored as 00:00:00, or midnight. I assume that what is happening is that the adjustment for daylight savings time (1 hour) is subtracting an hour from this time, thereby rolling it back to the day before.
My final question stands: is there a means to reliably prevent this error from occurring rather than manually checking for inaccurate dates (or programming in daylight savings time dates)?
I know this looks simple.
In a Google spreadsheet, I have a column where I enter time in one timezone (GMT)
And another column should automatically get time in another time zone(Pacific Time)
GMT | PT
----------|------------
5:00 AM | 9:00 PM
As of now I am using
=$C$3-time(8,0,0)
The problem here is, I want to change the time formula for Daylight savings.
Is there any function or script available which can take the daylight saving into calculation automatically.
Short answer
There is no built-in function but you could build a custom function.
Example
/**
* Converts a datetime string to a datetime string in a targe timezone.
*
*#param {"October 29, 2016 1:00 PM CDT"} datetimeString Date, time and timezone.
*#param {"Timezone"} timeZone Target timezone
*#param {"YYYY-MM-dd hh:mm a z"} Datetime format
*#customfunction
*/
function formatDate(datetimeString,timeZone,format) {
var moment = new Date(datetimeString);
if(moment instanceof Date && !isNaN(moment)){
return Utilities.formatDate(moment, timeZone, format)
} else {
throw 'datetimeString can not be parsed as a JavaScript Date object'
}
}
NOTE:
new Date(string) / Date.parse(string) implementation in Google Apps Script doesn't support some timezones abbreviations.
From https://tc39.es/ecma262/#sec-date-time-string-format
There exists no international standard that specifies abbreviations for civil time zones like CET, EST, etc. and sometimes the same abbreviation is even used for two very different time zones.
Related
Get UTC offset from timezone abbreviations
Explanation
In order to consider daylight saving time zones the input argument for of the value to be converted should include the date, no only the time of the day. You could set a default date and time zone to build the datetimeString by concatenating it before calling the formula.
=formatDate("October 29, 2016 "&A2&" GMT","PDT","hh:mm a")
For the target timezone besides the three letter abbreviation we could use TZ database names like America/Los_Angeles, example:
=formatDate("October 29, 2016 "&A2&" GMT","America/Los_Angeles","HH:mm")
If timezone abbreviation and TZ name fails for the datetimeString use time offsets (i.e. UTC-4).
See also
Calculating year, month, days between dates in google apps script
References
https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Date
This tutorial was amazingly helpful: https://davidkeen.com/blog/2017/01/time-zone-conversion-in-google-sheets/
Google Sheets does not have a built in way of converting time zone data but by using the power of Moment.js and Google’s script editor we can add time zone functionality to any sheet.
These are the files I copied into my script project:
https://momentjs.com/downloads/moment-with-locales.js saved as moment.js
https://momentjs.com/downloads/moment-timezone-with-data.js saved as moment-timezone.js
Make sure you add the moment.js script first and have it above the moment-timezone.js script because moment-timezone.js depends on it.
Then in your other script project, your Code.gs file can look like this:
var DT_FORMAT = 'YYYY-MM-DD HH:mm:ss';
/**
https://stackoverflow.com/questions/34946815/timezone-conversion-in-a-google-spreadsheet/40324587
*/
function toUtc(dateTime, timeZone) {
var from = m.moment.tz(dateTime, DT_FORMAT, timeZone);//https://momentjs.com/timezone/docs/#/using-timezones/parsing-in-zone/
return from.utc().format(DT_FORMAT);
}
/**
https://stackoverflow.com/questions/34946815/timezone-conversion-in-a-google-spreadsheet/40324587
*/
function fromUtc(dateTime, timeZone) {
var from = m.moment.utc(dateTime, DT_FORMAT);//https://momentjs.com/timezone/docs/#/using-timezones/parsing-in-zone/
return from.tz(timeZone).format(DT_FORMAT);
}
The easiest method is using a simple calculation.
Use =NOW() command in sheets and subtract it with the time difference divided by 24.
Example:
IST to Colombia
=NOW()-(10.5/24)
The time difference from India to Colombia is 10hours and 50min, we need to subtract it from the "Now" time and divide it by 24.
If the time zone is ahead of your place, then you need to add it.
Example:
IST to JAPAN:
=NOW()+(3.5/24)
=Now is set to US time by default, you can change it under general in settings.
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I had the same problem (convert Manila Time to Sydney Time and automatically adjust for daylight saving time) when I found this page.
I didn't want to have a custom function but I found that, in Sydney, AEST (Australian Eastern Standard Time) starts on the first Sunday of April and AEDT (Australian Eastern Daylight Time) starts on the first Sunday of October.
So I thought, if I could find a formula that detects whether a date falls between the first Sunday of April and first Sunday of October (Standard Time) then I can automatically add 1 hour to the usual 2 hours to Manila time during Daylight Saving Time (dates falling outside the two dates) to have Sydney Time.
These two Excel solutions worked fine in Google Sheets:
How You Can Determine the First Sunday in a Month in Excel
How to determine if a date falls between two dates or on weekend in Excel
First Sunday of April this year (A1):
=CONCATENATE("4/1/",Year(today()))+CHOOSE(WEEKDAY(CONCATENATE("4/1/",Year(today())),1),7,6,5,4,3,2,1)
First Sunday of October this year (A2):
=CONCATENATE("10/1/",year(today()))+CHOOSE(WEEKDAY(CONCATENATE("10/1/",year(today())),1),7,6,5,4,3,2,1)
DST detector (A3) — if a date falls outside these two dates, it's DST in Sydney:
=IF(AND(today()>A1,today()<A2),"AEST","AEDT")
Time in Sydney (A4):
=NOW()+TIME(IF(A3="AEDT",3,2),0,0)
NOW() can be changed to any time format for tabulation:
I'm a new contributor and a novice, but I stumbled upon a function that had not been mentioned despite many hours of searching on the Sheets/Time Zone issue. Hoping this relatively simple solution will help.
For my sheet, I just want to add a row and automatically populate the local sheet date and time in the first two cells.
The .getTimezoneOffset() returns the difference in minutes between the client TZ and GMT, which in NY during Daylight Savings Time is 240. The function returns a positive number for the zones with "GMT-x", and vice versa for zones with "GMT+x". Hence the need to divide by -60 to get the correct hour and sign.
function addRow() {
var ss = SpreadsheetApp.getActiveSpreadsheet();
var sheet = ss.getActiveSheet();
sheet.insertRows(2, 1);
rightNow = new Date();
var tzOffset = "GMT" + rightNow.getTimezoneOffset() / -60;
var fDate = Utilities.formatDate(rightNow, tzOffset, "MM-dd-yyyy");
var fTime = Utilities.formatDate(rightNow, tzOffset, "HH:mm");
sheet.getRange('A2').setValue(fDate);
sheet.getRange('B2').setValue(fTime);
sheet.getRange('C2').setValue(tzOffset);
}
I've since found that I'm not the first person to respond to the GMT correction connundrum mentioning .getTimezoneOffset(). However, this thread has the most views on this topic, so I figured this option deserves a mention.
DST ends here on November 7th, 2021, so I'll report back if it doesn't adjust as expected to "GMT-5"
.getTimezoneOffset()
That can also be done without macros. Just using functions and data manipulation will suffice. Explaning the whole process here would be a bit cumbersome. Just do your research on how the various time functions work and use your creativity.
Hint: Use =NOW() if you want both current date and time. You'll actually need that if you need to find out the precise diff in time between to different dates.
Use =NOW()-INT(NOW()) when you only want the time (with date truncated if both times fall on the same date). Then format the corresponding cell or cells for time (i.e. 4:30 PM), not for date-time (3/25/2019 17:00:00). The latter is the format you'd use when you want to show both date and time... like when you use NOW().
Also search online for the Daylight Saving Time offset for the various standard time zones (PT, MT, CT, ET, AT) with respect to the Coordinated Universal Time (UTC). For example, in 2019 the offset for Pacific Time is UTC-7 when DST is observed starting on March 10 at 2 AM (Pacific) until November 3 at 2 AM. That means that the difference in time from UTC to Pacific is 7 hours. During the rest of the year is 8 hours (UTC-8). During DST observance starting sometime in March (the 10th this yr) it goes from PST to PDT by moving clocks forward 1 hr, or what we know as UTC-7 (that's summer time). After DST observance it goes from PDT to PST by moving clocks back 1 hr again, or what we know as UTC-8 (or winter time). Remember that the clock is advanced one hour in March to make better use of time. That's what we call DST, or Daylight Saving Time. So after March 8 at 2 AM (this year in 2019) we are in UTC-7. In November, we do the opposite. In Nov 3 at 2 AM the clock is taken back one hour as the winter kicks in. At that point we are back in Standard Time. Seems a bit confusing but it's really not.
So, basically, for folks in PT they go from PST to PDT in March and from PDT to PST in November. The exact same process goes on with Mountain Time, Central Time and Eastern Time. But they have different UTC time offsets. MT is either UTC-6 or UTC-7. CT is either UTC-5 or UTC-6. And ET is either UTC-4 or UTC-5. All depending on whether we are in summer time when Daylight Saving is observed to make better use of daylight and working hours, or in winter time (AKA, Standard Time).
Study these thoroughly and understand how they work, and play around with the various time functions in Excel or Google Sheets like the TIME(#,#,#) and NOW() functions and such, and believe me, soon you'll be able to do about anything like a pro with plain functions without having to use VBA Google Apps Script. You can also use the TEXT() function, though, with tricks like =TEXT(L4,"DDD, MMM D")&" | "&TEXT(L4,"h:mm AM/PM"), where L4 contains you date-timestamp, to display time and date formats. The VALUE() function also comes in handy every now and then. You can even design a numerical countdown timer without the use of macros. You'd need to create a circular reference and set iterations to 1, and time display to say every 1 min, in your spreadsheet settings for that.
The official timeanddate dot com website is a good source of info for all to know about time zones and how daylight time is handled. They have all UTC offsets there too.
Create your own Timezone Converter in Google Sheets:
Step 1: Create your table for the timezone converter.
Step 2: Enter the times for your time zones in a column.
Note: Ensure that you select date/time format(Select Cell(s) -> Format -> Number -> Time/Date)
Step 3: Write a formula to convert timezone using the following functions
Google Sheet Functions
=HOUR(A8)+(B3*C3) converts the hours.
=MINUTE(A8)+(B3*C3) converts the minutes.
Step 4: Convert back to time format using TIME(h,m,s) function
=TIME(HOUR(A8)+(B3*C3), MINUTE(A8)+(B3*C3), SECOND(A8))
This is a simple way to convert timezones.
However, if you want to implement an accurate timezone converter that takes care of the previous day, next day, and beyond 24 hours, beyond 60 minutes, please use MOD operations and handle all the cases.
Visit(or Use) this google sheet for reference:
https://docs.google.com/spreadsheets/d/1tfz5AtU3pddb46PG93HFlzpE8zqy421N0MKxHBCSqpo/edit?usp=sharing
just use the TZData format to "pull" a sync from UTC and display your choice.
Example in order to "change" the display of your cell to Berlin local time
=fromUTC(N82, "Europe/Berlin")
or for Tokyo
=fromUTC(N82, "Asia/Tokyo")
or San Francisco
=fromUTC(N82, "America/Inuvik")
point of reference for Time Zones is here >>
https://en.wikipedia.org/wiki/List_of_tz_database_time_zones
I have a problem where when saving a datetime attribute, the form returns -04:00 instead of -05:00
Using Rails 3.2.3
In application.rb:
config.time_zone = 'Eastern Time (US & Canada)'
Using MySQL with mysql2 adapter
Running #wine.released_at.localtime returns 2008-05-15 00:00:00.000000000 -04:00
Running #wine.released_at returns 2008-05-15 04:00:00.000000000 Z
Running Time.now.zone returns Eastern Standard Time
Running #wine.released_at.zone returns EDT
I'm fairly confused. I though setting config.time_zone should make it such that Rails automatically converts all database datetime values to the set time_zone...why isn't this happening?
It looks to me as if the zone property returns the name of the "zone interval" which is applicable for the specified time. So for a summer time it will return "EDT" but for a winter time it will return "Easter Standard Time". (It's odd that it uses an abbreviation for one but not the other, but hey...)
So it is using the same time zone for both - those are just different aspects within the same time zone: sometimes it's standard time, sometimes it's daylight saving time.
If you print Time.now.localtime it should show you a -05:00 to show that the current offset from UTC in Eastern Time is -5 hours (i.e. Eastern Time is currently 5 hours behind UTC).
Have you tried using in_time_zone?
I'm have access to a 3rd party application's database, and I see a field called "date" which stores date/time values as floating point numbers, but I'm not sure how this floating point number is mapped to a date/time. There is no documentation for this database.
Here is some sample data:
date-field actual-date-time
253507382.168744 1/12/09 6:43 PM PST
253507480.136126 1/12/09 6:44 PM PST
253508091.838982 1/12/09 6:54 PM PST
256703604.015055 2/18/09 6:33 PM PST
256704413.484674 2/18/09 6:46 PM PST
Note: I had to enter these values manually so there's a slight chance they may be off a bit. If you would like to see more data, let me know and I'll add more.
I'm hoping someone is familiar with storing dates in this format and can let me know how to get a date/time given a floating point number.
If you look at the change in the numbers over the 10 and 13 minute intervals, you'll see that it's about 60. Therefore I conclude that it's a count of the number of seconds from a base date.
I think the base date is 1/1/2000 or 1/1/2001.
Edit: The base date appears to be 1/1/2001, and the time appears to be adjusted as well - it's probably UTC with your local time offset added.
If you subtract any of the two points you'll see that the values represent the number of seconds, at microsecond accuracy. It should be easy to work out the base date where the clock "started". On Unix and related systems this is January 1st, 1970.
The timestamps are 'number of seconds elapsed since 00:00 on January 1st 2001'. It's not a common date format but at least it should be easy to work with now you know what it represents!