#Shanghai gmt time zone how to#
#Shanghai gmt time zone plus#

It was originally meant to make better use of natural daylight and reduce electricity consumptionĮach zone, country, or region may have a time zone that changes over time (e.g. The time zone is basically an offset of UTC, but it may also be subject to an additional change during Daylight Saving Time: Daylight Saving Time (DST), also known as summer time, is observed by advancing clocks one hour in the spring and then reverting to standard time in the autumn. Time Zones and Local TimeĪ time zone is a region of the globe that observes a uniform standard time. Strictly speaking, though, the current time reference is not GMT but UTC. Practically speaking, GMT time is the equivalent of UTC time (GMT = UTC+0). No place on earth uses UTC as an official time zone GMT is used as a time zone in the UK and in parts of Africa. UTC is a time reference GMT is a time zone. Nowadays, GMT is currently used as a time zone that has no offset from UTC. So noon GMT was the moment when the sun was at its highest point above the Greenwich Meridian. Greenwich, a borough of London that is home to the prime meridian (0o longitude) was chosen as this point. When the original time reference had to be defined, it was agreed to make it relative to a certain point on earth.

#Shanghai gmt time zone plus#

So the local time for this region would be the current UTC time plus one hour. For instance, the Central European Time Zone is defined as UTC+1:00. Real-time estimates of UTC are computed and provided by different centers, such as the United States Naval Observatory and the National Institute of Standards and Technology.įrom this reference point, each time zone derives a local time that is represented as an offset from UTC. UTC is obtained by applying a set of algorithms to about 250 cesium clocks and hydrogen masers in roughly 65 different laboratories worldwide. UTC evolved from Greenwich Mean Time (GMT) for use as a standard and is maintained by the Bureau International des Poids et Mesures in Paris. Since time needs to be known and coordinated across the entire world, Coordinated Universal Time (UTC) is used as the standard absolute time reference. We’ll start with the standard time reference.

“Records with a local date segment equal to user’s date segment”īefore we talk about using date and time data in MySQL, let’s review how time zones work.Is the information going to be sorted or filtered by its local time or by its UTC representation?.How is this data going to be displayed?.

Does this data represent a point in time in the past or in the future?.

Time zones and time offsets are not the same thing.

It is important to notice that these concepts apply when representing a point in time rather than an absolute duration. Let’s first address some core concepts that will help us understand the underlying complexity of time-related data.

#Shanghai gmt time zone how to#

We’ll also look at how to handle multiple time zones and daylight saving time changes. In this article, I’ll walk you through some fundamental considerations for working with date- and time-related data in MySQL.