How to Get Gmt Time in Unix

How to convert GMT date time into GMT Unix TimeStamp using JS?

Without a timezone, new Date assumes localtime

so, lets say you retrieve the string

var date = '2018-08-21 11:37:56';

what you can do is

var date = '2018-08-21 11:37:56';var t = new Date(date.replace(' ', 'T') + 'Z').getTime() / 1000;console.log(t); // 1534851476 - see for yourself

Getting date in GMT from unix timestamp

This is the problem, conceptually:

//date obtained here is in IST on my system which needs to be converted into GMT.
Date time = new Date(Long.valueOf(unixTimeStamp) * 1000);

A Date doesn't have a time zone. This is the value you want. The fact that when you call toString() it converts it to your local time zone is irrelevant to the value that it's actually representing. A Date is just a number of milliseconds since the Unix epoch (1st January 1970, midnight UTC). So your whole method can be:

private static Date convertToDate(String unixTimeStamp)
{
    return new Date(Long.valueOf(unixTimeStamp) * 1000);
}

You don't need any kind of formatter, as you're not really trying to get a textual representation.

I would advise you to use Joda Time for date/time work if you can, by the way - it's a much cleaner API.

UNIX timestamp always in GMT?

yep, UNIX timestamp represents how much seconds past from unix-time epoch in GMT+0

How to get GMT date from Unix epoch time milliseconds?

Change calendar.setTimeInMillis(time / 1000) to calendar.setTimeInMillis(time * 1000)

The number of milliseconds is 1000 times the number of seconds; not 1/1000 the number.

How to convert timestamp from GMT to Unix epoch

SimpleDateFormat is outdated, as Gael pointed out.

The Time API now supports up to nanoseconds, so microseconds are not an issue here. You should use DateTimeFormatter with ZonedDateTime. Your pattern is slightly wrong. Checking the docs for Offset Z:

Offset Z: This formats the offset based on the number of pattern
letters. One, two or three letters outputs the hour and minute,
without a colon, such as '+0130'. The output will be '+0000' when the
offset is zero. Four letters outputs the full form of localized
offset, equivalent to four letters of Offset-O. The output will be the
corresponding localized offset text if the offset is zero. Five
letters outputs the hour, minute, with optional second if non-zero,
with colon. It outputs 'Z' if the offset is zero. Six or more letters
throws IllegalArgumentException.

You can also print the time using toInstant to make sure it was parsed correctly:

  import java.time.ZonedDateTime
  import java.time.format.DateTimeFormatter

  val parsed = "2022-01-12T17:17:34.512492+0000"
  val p = "yyyy-MM-dd'T'HH:mm:ss.SSSSSSZZZ"
  val dtf = DateTimeFormatter.ofPattern(p)
  val zdt = ZonedDateTime.parse(parsed, dtf)
  println(zdt.toInstant) // 2022-01-12T17:17:34.512492Z
  println(zdt.toInstant.toEpochMilli) // 1642004254512

Here is a nice article that explains in detail converting an ISO 8601 in Java. The comments at the end are particularly useful, as it shows the difference between the different patterns used.

How to convert GMT date to UNIX time in golang?

The layout of the date is RFC1123. Parse it with time.Parse() then convert it to Unix with time.Time.Unix().

t, _ := time.Parse(time.RFC1123, "Mon, 23 Dec 2019 18:52:45 GMT")
tUnix:= t.Unix()
fmt.Printf("%s in Unix is %d",t,tUnix)
// Output: 2019-12-23 18:52:45 +0000 GMT in Unix is 1577127165

Try it online

How to change timezone from GMT+0 to GMT+2 of this Unix epoch time (Milliseconds) conversion Query?

I found a way to do this and it works nicely for my specific needs. Here is my Query;

LEFT(DATEADD(SECOND, FLOOR([epochtime_column]/1000 ), '1970-01-01') AT TIME ZONE 'UTC' at TIME ZONE 'Central European Standard Time', 19)

You basically chop off the 3 added numbers from the epoch time in milliseconds to turn it into epoch time in seconds. After which you add those seconds up to 1970-01-01 to turn it into a readable date.

This is only a viable strategy when you don't need the milliseconds from the epoch time. IF you do need the milliseconds then this solution will not work for you.

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