• MYSQL 版本：MYSQL 5.7.38-221001-log

基本概念

GMT(格林尼治标准时间、世界时间) 与 UTC(协调世界时间)

GMT(格林尼治标准时间、世界时间) 【不推荐】、UTC(协调世界时间) 【推荐】

• ‌GMT(Greenwich Mean Time,格林威治标准时间)‌：GMT是基于地球自转和对恒星的观测来定义的时间标准，将地球划分为24个时区。

它以英国伦敦郊区的格林尼治天文台为参考点，当太阳在每年的某一天通过格林尼治子午线的时刻为中午12点。
GMT曾经是国际上主要的时间标准，但由于地球自转速度会有微小的变化，GMT并不是一个非常精确的时间标准。

• ‌UTC‌(Coordinated Universal Time,协调的世界时间)：UTC是在GMT的基础之上，基于原子时钟的测量，让世界各地的时差保持一致。

这些原子时钟的精度非常高，几乎不受环境因素影响。
UTC由国际时间标准组织（法国人发起）维护，并通过增加或减少闰秒来校正地球自转速度的微小变化，以保持与GMT的一致性。）维护，并通过增加或减少闰秒来校正地球自转速度的微小变化，以保持与GMT的一致性。
UTC是当前国际上最广泛使用的时间标准**，被用于全球的时间服务、互联网、航空等领域。
UTC比GMT更为精确，误差值必须保持在0.9秒以内。

-- mysql 5.7
> set time_zone = 'UTC';
> select CURTIME()
CURTIME()|
---------+
 12:53:29|

> set time_zone = 'GMT';
> select CURTIME()
CURTIME()|
---------+
 12:53:29|

• 时间偏移的对比

由于地球自转轴的倾斜和地球公转轨道的椭圆形状，地球上不同地区的太阳高度角和白昼时间会有所不同。
这导致了GMT在跨越经度较大的地区时，时间会出现较大的偏差。
而UTC则能较好地反映地球的真实形状，因此在跨越经度较大的地区时，时间偏差较小。

• 在实际应用中，UTC通常被认为是更现代和精确的时间标准，尤其是在需要高精度时间的情况下，UTC是首选的时间标准。

尽管GMT和UTC之间通常差异很小，但在需要高精度的时间应用中，UTC更为适用。
在互联网中，UTC时间系统被应用与许多互联网和万维网的标准中，网络时间协议就是协调世界时(UTC)的一种使用方式。
在军事中，UTC时区会使用Z来表示。又由于Z在无线电联络中使用Zulu作代称，协调世界时也会被称为Zulu time

yyyy-MM-dd'T'HH:mm:ss.SSS'Z'

• 推荐文献

• GMT和UTC有什么区别？ – 虎牙视频

可直观地了解GMT和UTC的区别

• “GMT与UTC:全球时间的微妙差异” – 慕课网

CST(中国标准时间)

• CST时间(China Standard Time, 中国标准时间)

在时区划分上，属东八区，比协调世界时早8小时，记为UTC+8。

CST时间：China Standard Time，即中国标准时间。在时区划分上，属东八区，比协调世界时早8小时，记为UTC+8。

(UNIX)时间戳

• UNIX时间戳（timestamp）：计算机中的UNIX时间戳，是以GMT/UTC时间1970-01-01T00:00:00为起点，到当前具体时间的秒数(不考虑闰秒)。

这样做的目的，主要是通过“整数计算”来简化计算机对时间操作的复杂度。

Linux 的时间操作

获取时间

• 获取本地时间

root@xxx:~# date
Wed Nov 27 09:12:59 PM CST 2024

root@xxx:~# date +'%Y-%m-%d %H:%M:%S.%s'
2024-11-27 21:13:20.1732713200

• 获取UTC时间

root@xxx:~# date +'%Y-%m-%d %H:%M:%S.%s' -u
2024-11-27 13:14:04.1732713244

root@xxx:~# date; date -u
Wed Nov 27 09:14:46 PM CST 2024
Wed Nov 27 01:14:46 PM UTC 2024

可见，与本地时间(UTC+8)确实相差8小时

• date命令的参数

• %T 时间（24小时制）（hh:mm:ss）
• %y 年的最后两个数字（ 1999则是99）
• %Y 年（例如：1970，1996等）
• %m 月（01..12）
• %d 日、一个月的第几天（01..31）
• %D 日期（mm／dd／yy）
• %j 一年的第几天（001..366）
• %H 小时（00..23）
• %M 分（00..59）
• %S 秒（00..59）
• %s 从1970年1月1日00：00：00到目前经历的秒数
• %N 从1970年1月1日00：00：00到目前经历的纳秒

> date +%s.%N
1715409477.512093100

> DATE_STR=$(date +'%Y-%m-%d %H:%M:%S')
> DATE_STR=$(date +'%Y%m%d%H%M%S')
> echo $DATE_STR
2023-04-15 21:08:35

# 字符串拼接方式(秒级时间戳 + 毫秒级的3位)
> echo $(date +%s)$(( "$(echo  $(date +%N) | awk '{print $0+0}' )/1000000" ))
> echo $(date +%s)$( echo $(( "$(echo  $(date +%N) | awk '{print $0+0}' )/1000000" )) | awk '{printf("%03d\n",$0)}' )
1715409575298

# 字符串拼接方式(秒级时间戳 + 毫秒级的3位) + 字符串转为数值
> echo $( expr $((  $(date +%s)$( echo $(( "$(echo  $(date +%N) | awk '{print $0+0}' )/1000000" )) | awk '{printf("%03d\n",$0)}' ) )) \* 1 )
1715409575298

获取时间戳

获取时间戳，不管是UTC时间还是北京时间 时间戳都是一样
是以GMT/UTC时间1970-01-01T00:00:00为起点，到当前具体时间的秒数(不考虑闰秒)

root@xxx:~# date +%s;date +%s -u
1732713357
1732713357

将【时间戳】转为时间字符串

[root@chb1 ~]# date -d @1682137164
Sat Apr 22 12:19:24 CST 2023

[root@chb1 ~]# date -d @1682137164 +'%Y-%m-%d %H:%M:%S.%s'
2023-04-22 12:19:24.1682137164

[root@chb1 ~]# date -d @1682137164 +'%Y-%m-%d %H:%M:%S.%s' -u
2023-04-22 04:19:24.1682137164

获取当前系统时区

• 可以通过 date +%Z 或者 timedatectl

root@xxx:~# date +%Z
CST

root@xxx:~# date +%z
+0800

root@xxx:~# timedatectl
               Local time: Wed 2024-11-27 21:11:04 CST
           Universal time: Wed 2024-11-27 13:11:04 UTC
                 RTC time: Wed 2024-11-27 13:11:04
                Time zone: Asia/Shanghai (CST, +0800)
System clock synchronized: yes
              NTP service: active
          RTC in local TZ: no

查看时区配置文件:/etc/localtime

root@xxx:~# ls -l /etc/localtime
lrwxrwxrwx 1 root root 33 Jul  7 12:11 /etc/localtime -> /usr/share/zoneinfo/Asia/Shanghai

Java 的时间操作

获取可用的时区

Java一共定义了 603个 时区，这些时区的名字是不需要你去背的，在 java.time.ZoneId 这个类中有一个方法可以获取到：getAvailableZoneIds()

这个方法是 static 静态方法，因此我们直接用类名直接调用就行了。

• 获取所有可用的时区

static Set<string> getAvailableZoneIds()  // 获取Java中支持的所有时区名称

["Asia/Aden","America/Cuiaba","Etc/GMT+9","Etc/GMT+8","Africa/Nairobi","America/Marigot","Asia/Aqtau","Pacific/Kwajalein","America/El_Salvador","Asia/Pontianak","Africa/Cairo","Pacific/Pago_Pago","Africa/Mbabane","Asia/Kuching","Pacific/Honolulu","Pacific/Rarotonga","America/Guatemala","Australia/Hobart","Europe/London","America/Belize","America/Panama","Asia/Chungking","America/Managua","America/Indiana/Petersburg","Asia/Yerevan","Europe/Brussels","GMT","Europe/Warsaw","America/Chicago","Asia/Kashgar","Chile/Continental","Pacific/Yap","CET","Etc/GMT-1","Etc/GMT-0","Europe/Jersey","America/Tegucigalpa","Etc/GMT-5","Europe/Istanbul","America/Eirunepe","Etc/GMT-4","America/Miquelon","Etc/GMT-3","Europe/Luxembourg","Etc/GMT-2","Etc/GMT-9","America/Argentina/Catamarca","Etc/GMT-8","Etc/GMT-7","Etc/GMT-6","Europe/Zaporozhye","Canada/Yukon","Canada/Atlantic","Atlantic/St_Helena","Australia/Tasmania","Libya","Europe/Guernsey","America/Grand_Turk","US/Pacific-New","Asia/Samarkand","America/Argentina/Cordoba","Asia/Phnom_Penh","Africa/Kigali","Asia/Almaty","US/Alaska","Asia/Dubai","Europe/Isle_of_Man","America/Araguaina","Cuba","Asia/Novosibirsk","America/Argentina/Salta","Etc/GMT+3","Africa/Tunis","Etc/GMT+2","Etc/GMT+1","Pacific/Fakaofo","Africa/Tripoli","Etc/GMT+0","Israel","Africa/Banjul","Etc/GMT+7","Indian/Comoro","Etc/GMT+6","Etc/GMT+5","Etc/GMT+4","Pacific/Port_Moresby","US/Arizona","Antarctica/Syowa","Indian/Reunion","Pacific/Palau","Europe/Kaliningrad","America/Montevideo","Africa/Windhoek","Asia/Karachi","Africa/Mogadishu","Australia/Perth","Brazil/East","Etc/GMT","Asia/Chita","Pacific/Easter","Antarctica/Davis","Antarctica/McMurdo","Asia/Macao","America/Manaus","Africa/Freetown","Europe/Bucharest","Asia/Tomsk","America/Argentina/Mendoza","Asia/Macau","Europe/Malta","Mexico/BajaSur","Pacific/Tahiti","Africa/Asmera","Europe/Busingen","America/Argentina/Rio_Gallegos","Africa/Malabo","Europe/Skopje","America/Catamarca","America/Godthab","Europe/Sarajevo","Australia/ACT","GB-Eire","Africa/Lagos","America/Cordoba","Europe/Rome","Asia/Dacca","Indian/Mauritius","Pacific/Samoa","America/Regina","America/Fort_Wayne","America/Dawson_Creek","Africa/Algiers","Europe/Mariehamn","America/St_Johns","America/St_Thomas","Europe/Zurich","America/Anguilla","Asia/Dili","America/Denver","Africa/Bamako","Europe/Saratov","GB","Mexico/General","Pacific/Wallis","Europe/Gibraltar","Africa/Conakry","Africa/Lubumbashi","Asia/Istanbul","America/Havana","NZ-CHAT","Asia/Choibalsan","America/Porto_Acre","Asia/Omsk","Europe/Vaduz","US/Michigan","Asia/Dhaka","America/Barbados","Europe/Tiraspol","Atlantic/Cape_Verde","Asia/Yekaterinburg","America/Louisville","Pacific/Johnston","Pacific/Chatham","Europe/Ljubljana","America/Sao_Paulo","Asia/Jayapura","America/Curacao","Asia/Dushanbe","America/Guyana","America/Guayaquil","America/Martinique","Portugal","Europe/Berlin","Europe/Moscow","Europe/Chisinau","America/Puerto_Rico","America/Rankin_Inlet","Pacific/Ponape","Europe/Stockholm","Europe/Budapest","America/Argentina/Jujuy","Australia/Eucla","Asia/Shanghai","Universal","Europe/Zagreb","America/Port_of_Spain","Europe/Helsinki","Asia/Beirut","Asia/Tel_Aviv","Pacific/Bougainville","US/Central","Africa/Sao_Tome","Indian/Chagos","America/Cayenne","Asia/Yakutsk","Pacific/Galapagos","Australia/North","Europe/Paris","Africa/Ndjamena","Pacific/Fiji","America/Rainy_River","Indian/Maldives","Australia/Yancowinna","SystemV/AST4","Asia/Oral","America/Yellowknife","Pacific/Enderbury","America/Juneau","Australia/Victoria","America/Indiana/Vevay","Asia/Tashkent","Asia/Jakarta","Africa/Ceuta","Asia/Barnaul","America/Recife","America/Buenos_Aires","America/Noronha","America/Swift_Current","Australia/Adelaide","America/Metlakatla","Africa/Djibouti","America/Paramaribo","Asia/Qostanay","Europe/Simferopol","Europe/Sofia","Africa/Nouakchott","Europe/Prague","America/Indiana/Vincennes","Antarctica/Mawson","America/Kralendijk","Antarctica/Troll","Europe/Samara","Indian/Christmas","America/Antigua","Pacific/Gambier","America/Indianapolis","America/Inuvik","America/Iqaluit","Pacific/Funafuti","UTC","Antarctica/Macquarie","Canada/Pacific","America/Moncton","Africa/Gaborone","Pacific/Chuuk","Asia/Pyongyang","America/St_Vincent","Asia/Gaza","Etc/Universal","PST8PDT","Atlantic/Faeroe","Asia/Qyzylorda","Canada/Newfoundland","America/Kentucky/Louisville","America/Yakutat","Asia/Ho_Chi_Minh","Antarctica/Casey","Europe/Copenhagen","Africa/Asmara","Atlantic/Azores","Europe/Vienna","ROK","Pacific/Pitcairn","America/Mazatlan","Australia/Queensland","Pacific/Nauru","Europe/Tirane","Asia/Kolkata","SystemV/MST7","Australia/Canberra","MET","Australia/Broken_Hill","Europe/Riga","America/Dominica","Africa/Abidjan","America/Mendoza","America/Santarem","Kwajalein","America/Asuncion","Asia/Ulan_Bator","NZ","America/Boise","Australia/Currie","EST5EDT","Pacific/Guam","Pacific/Wake","Atlantic/Bermuda","America/Costa_Rica","America/Dawson","Asia/Chongqing","Eire","Europe/Amsterdam","America/Indiana/Knox","America/North_Dakota/Beulah","Africa/Accra","Atlantic/Faroe","Mexico/BajaNorte","America/Maceio","Etc/UCT","Pacific/Apia","GMT0","America/Atka","Pacific/Niue","Australia/Lord_Howe","Europe/Dublin","Pacific/Truk","MST7MDT","America/Monterrey","America/Nassau","America/Jamaica","Asia/Bishkek","America/Atikokan","Atlantic/Stanley","Australia/NSW","US/Hawaii","SystemV/CST6","Indian/Mahe","Asia/Aqtobe","America/Sitka","Asia/Vladivostok","Africa/Libreville","Africa/Maputo","Zulu","America/Kentucky/Monticello","Africa/El_Aaiun","Africa/Ouagadougou","America/Coral_Harbour","Pacific/Marquesas","Brazil/West","America/Aruba","America/North_Dakota/Center","America/Cayman","Asia/Ulaanbaatar","Asia/Baghdad","Europe/San_Marino","America/Indiana/Tell_City","America/Tijuana","Pacific/Saipan","SystemV/YST9","Africa/Douala","America/Chihuahua","America/Ojinaga","Asia/Hovd","America/Anchorage","Chile/EasterIsland","America/Halifax","Antarctica/Rothera","America/Indiana/Indianapolis","US/Mountain","Asia/Damascus","America/Argentina/San_Luis","America/Santiago","Asia/Baku","America/Argentina/Ushuaia","Atlantic/Reykjavik","Africa/Brazzaville","Africa/Porto-Novo","America/La_Paz","Antarctica/DumontDUrville","Asia/Taipei","Antarctica/South_Pole","Asia/Manila","Asia/Bangkok","Africa/Dar_es_Salaam","Poland","Atlantic/Madeira","Antarctica/Palmer","America/Thunder_Bay","Africa/Addis_Ababa","Asia/Yangon","Europe/Uzhgorod","Brazil/DeNoronha","Asia/Ashkhabad","Etc/Zulu","America/Indiana/Marengo","America/Creston","America/Punta_Arenas","America/Mexico_City","Antarctica/Vostok","Asia/Jerusalem","Europe/Andorra","US/Samoa","PRC","Asia/Vientiane","Pacific/Kiritimati","America/Matamoros","America/Blanc-Sablon","Asia/Riyadh","Iceland","Pacific/Pohnpei","Asia/Ujung_Pandang","Atlantic/South_Georgia","Europe/Lisbon","Asia/Harbin","Europe/Oslo","Asia/Novokuznetsk","CST6CDT","Atlantic/Canary","America/Knox_IN","Asia/Kuwait","SystemV/HST10","Pacific/Efate","Africa/Lome","America/Bogota","America/Menominee","America/Adak","Pacific/Norfolk","Europe/Kirov","America/Resolute","Pacific/Tarawa","Africa/Kampala","Asia/Krasnoyarsk","Greenwich","SystemV/EST5","America/Edmonton","Europe/Podgorica","Australia/South","Canada/Central","Africa/Bujumbura","America/Santo_Domingo","US/Eastern","Europe/Minsk","Pacific/Auckland","Africa/Casablanca","America/Glace_Bay","Canada/Eastern","Asia/Qatar","Europe/Kiev","Singapore","Asia/Magadan","SystemV/PST8","America/Port-au-Prince","Europe/Belfast","America/St_Barthelemy","Asia/Ashgabat","Africa/Luanda","America/Nipigon","Atlantic/Jan_Mayen","Brazil/Acre","Asia/Muscat","Asia/Bahrain","Europe/Vilnius","America/Fortaleza","Etc/GMT0","US/East-Indiana","America/Hermosillo","America/Cancun","Africa/Maseru","Pacific/Kosrae","Africa/Kinshasa","Asia/Kathmandu","Asia/Seoul","Australia/Sydney","America/Lima","Australia/LHI","America/St_Lucia","Europe/Madrid","America/Bahia_Banderas","America/Montserrat","Asia/Brunei","America/Santa_Isabel","Canada/Mountain","America/Cambridge_Bay","Asia/Colombo","Australia/West","Indian/Antananarivo","Australia/Brisbane","Indian/Mayotte","US/Indiana-Starke","Asia/Urumqi","US/Aleutian","Europe/Volgograd","America/Lower_Princes","America/Vancouver","Africa/Blantyre","America/Rio_Branco","America/Danmarkshavn","America/Detroit","America/Thule","Africa/Lusaka","Asia/Hong_Kong","Iran","America/Argentina/La_Rioja","Africa/Dakar","SystemV/CST6CDT","America/Tortola","America/Porto_Velho","Asia/Sakhalin","Etc/GMT+10","America/Scoresbysund","Asia/Kamchatka","Asia/Thimbu","Africa/Harare","Etc/GMT+12","Etc/GMT+11","Navajo","America/Nome","Europe/Tallinn","Turkey","Africa/Khartoum","Africa/Johannesburg","Africa/Bangui","Europe/Belgrade","Jamaica","Africa/Bissau","Asia/Tehran","WET","Europe/Astrakhan","Africa/Juba","America/Campo_Grande","America/Belem","Etc/Greenwich","Asia/Saigon","America/Ensenada","Pacific/Midway","America/Jujuy","Africa/Timbuktu","America/Bahia","America/Goose_Bay","America/Virgin","America/Pangnirtung","Asia/Katmandu","America/Phoenix","Africa/Niamey","America/Whitehorse","Pacific/Noumea","Asia/Tbilisi","America/Montreal","Asia/Makassar","America/Argentina/San_Juan","Hongkong","UCT","Asia/Nicosia","America/Indiana/Winamac","SystemV/MST7MDT","America/Argentina/ComodRivadavia","America/Boa_Vista","America/Grenada","Asia/Atyrau","Australia/Darwin","Asia/Khandyga","Asia/Kuala_Lumpur","Asia/Famagusta","Asia/Thimphu","Asia/Rangoon","Europe/Bratislava","Asia/Calcutta","America/Argentina/Tucuman","Asia/Kabul","Indian/Cocos","Japan","Pacific/Tongatapu","America/New_York","Etc/GMT-12","Etc/GMT-11","America/Nuuk","Etc/GMT-10","SystemV/YST9YDT","Europe/Ulyanovsk","Etc/GMT-14","Etc/GMT-13","W-SU","America/Merida","EET","America/Rosario","Canada/Saskatchewan","America/St_Kitts","Arctic/Longyearbyen","America/Fort_Nelson","America/Caracas","America/Guadeloupe","Asia/Hebron","Indian/Kerguelen","SystemV/PST8PDT","Africa/Monrovia","Asia/Ust-Nera","Egypt","Asia/Srednekolymsk","America/North_Dakota/New_Salem","Asia/Anadyr","Australia/Melbourne","Asia/Irkutsk","America/Shiprock","America/Winnipeg","Europe/Vatican","Asia/Amman","Etc/UTC","SystemV/AST4ADT","Asia/Tokyo","America/Toronto","Asia/Singapore","Australia/Lindeman","America/Los_Angeles","SystemV/EST5EDT","Pacific/Majuro","America/Argentina/Buenos_Aires","Europe/Nicosia","Pacific/Guadalcanal","Europe/Athens","US/Pacific","Europe/Monaco"]

• 获取系统默认时区

static ZoneId systemDefault()	// 获取当前系统默认时区

• 指定时区

static Zoneld of(string zoneld)  // 指定一个时区

如:
ZoneId.of("Asia/Shanghai")
ZoneId.of("Asia/Tokyo")
ZoneId.of("UTC+08")
ZoneId.of("UTC")
ZoneId.of("GMT")

获取当前UTC时间

import java.time.ZonedDateTime;
import java.time.ZoneOffset;
 
public class TimeExample {
    public static void main(String[] args) {
        // 获取当前UTC时间
        ZonedDateTime utcNow = ZonedDateTime.now(ZoneOffset.UTC);// ZoneOffset.UTC or ZoneOffset.of("Asia/Shanghai") or ...
        System.out.println("Current UTC Time: " + utcNow);//Current UTC Time: 2024-11-27T13:29:36.840Z
    }
}

将本地时间转换为UTC时间

import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZonedDateTime;
 
public class LocalToUTCTimeExample {
    public static void main(String[] args) {
        // 获取当前本地时间
        LocalDateTime localNow = LocalDateTime.now();
        // 将本地时间转换为UTC时间
        ZonedDateTime utcTime = localNow.atZone(ZoneId.systemDefault()).withZoneSameInstant(ZoneOffset.UTC);
        System.out.println("Local Time to UTC: " + utcTime);
    }
}

时间字符串的解析（转为时间对象、转时间戳）

public static datetimeStrParse(){
	final ZoneId ZONE_CST = ZoneId.of("Asia/Shanghai");
	final DateTimeFormatter CST_PARSER = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss").withZone(ZONE_CST);

	String dateTimeString = "2024-11-24 08:40:00";
	ZonedDateTime dateTime = ZonedDateTime.parse(dateTimeString, CST_PARSER);
	Long ts = dateTime.toInstant().toEpochMilli();//获取时间戳
	System.out.println("ts: "+ ts + " dateTime: " + dateTime);//ts: 1732408800000 dateTime: 2024-11-24T08:40+08:00[Asia/Shanghai]
}

• DateTimeFormatter#Pattern的参数

• y：年份，例如”2022″
• M：月份，例如”01″
• d：天数，例如”01″
• H：小时（24小时制），例如”10″
• h：小时（12小时制），例如”10″或”10 PM”
• m：分钟数，例如”00″
• s：秒数，例如”00″
• S：毫秒数，例如”000″
• a：上午/下午标记，例如”AM”或”PM”
• E：星期几
• Z：时区

MYSQL 时间与时区概述

MYSQL 支持的时区

方式1：查看操作系统

在mysql文档中发现可用的时区都在/usr/share/zoneinfo目录下

lewis@lewis-dzwww:/usr/share/zoneinfo$ ll
总用量 308
drwxr-xr-x  21 root root  4096 5月  27 12:54 ./
drwxr-xr-x 334 root root 12288 6月  21 15:11 ../
drwxr-xr-x   2 root root  4096 5月  27 12:56 Africa/
drwxr-xr-x   6 root root  4096 5月  27 12:56 America/
drwxr-xr-x   2 root root  4096 5月  27 12:56 Antarctica/
drwxr-xr-x   2 root root  4096 5月  27 12:56 Arctic/
drwxr-xr-x   2 root root  4096 5月  27 12:56 Asia/
drwxr-xr-x   2 root root  4096 5月  27 12:56 Atlantic/
drwxr-xr-x   2 root root  4096 5月  27 12:56 Australia/
drwxr-xr-x   2 root root  4096 5月  27 12:56 Brazil/
drwxr-xr-x   2 root root  4096 5月  27 12:56 Canada/
-rw-r--r--   1 root root  2102 4月  21 02:09 CET
drwxr-xr-x   2 root root  4096 5月  27 12:56 Chile/
-rw-r--r--   1 root root  2294 4月  21 02:09 CST6CDT
-rw-r--r--   1 root root  2437 4月  21 02:09 Cuba
-rw-r--r--   1 root root  1876 4月  21 02:09 EET
-rw-r--r--   1 root root  1972 4月  21 02:09 Egypt
-rw-r--r--   1 root root  3559 4月  21 02:09 Eire
-rw-r--r--   1 root root   127 4月  21 02:09 EST
-rw-r--r--   1 root root  2294 4月  21 02:09 EST5EDT
drwxr-xr-x   2 root root  4096 5月  27 12:56 Etc/
drwxr-xr-x   2 root root  4096 5月  27 12:56 Europe/
-rw-r--r--   1 root root   264 4月  21 02:09 Factory
-rw-r--r--   1 root root  3687 4月  21 02:09 GB
lrwxrwxrwx   1 root root     2 5月  27 09:07 GB-Eire -> GB
-rw-r--r--   1 root root   127 4月  21 02:09 GMT
lrwxrwxrwx   1 root root     3 5月  27 09:07 GMT0 -> GMT
lrwxrwxrwx   1 root root     3 5月  27 09:07 GMT-0 -> GMT
lrwxrwxrwx   1 root root     3 5月  27 09:07 GMT+0 -> GMT
lrwxrwxrwx   1 root root     3 5月  27 09:07 Greenwich -> GMT
-rw-r--r--   1 root root  1189 4月  21 02:09 Hongkong
-rw-r--r--   1 root root   128 4月  21 02:09 HST
-rw-r--r--   1 root root  1190 4月  21 02:09 Iceland
drwxr-xr-x   2 root root  4096 5月  27 12:56 Indian/
-rw-r--r--   1 root root  1678 4月  21 02:09 Iran
-rw-r--r--   1 root root  4475 2月  24 17:01 iso3166.tab
-rw-r--r--   1 root root  2265 4月  21 02:09 Israel
-rw-r--r--   1 root root   507 4月  21 02:09 Jamaica
-rw-r--r--   1 root root   355 4月  21 02:09 Japan
-rw-r--r--   1 root root   237 4月  21 02:09 Kwajalein
-rw-r--r--   1 root root 10384 2月  22 23:58 leap-seconds.list
-rw-r--r--   1 root root   655 4月  21 02:09 Libya
lrwxrwxrwx   1 root root    14 5月  27 09:07 localtime -> /etc/localtime
-rw-r--r--   1 root root  2102 4月  21 02:09 MET
drwxr-xr-x   2 root root  4096 5月  27 12:56 Mexico/
-rw-r--r--   1 root root   127 4月  21 02:09 MST
-rw-r--r--   1 root root  2294 4月  21 02:09 MST7MDT
-rw-r--r--   1 root root  2453 4月  21 02:09 Navajo
-rw-r--r--   1 root root  2460 4月  21 02:09 NZ
-rw-r--r--   1 root root  2057 4月  21 02:09 NZ-CHAT
drwxr-xr-x   2 root root  4096 5月  27 12:56 Pacific/
-rw-r--r--   1 root root  2705 4月  21 02:09 Poland
-rw-r--r--   1 root root  3453 4月  21 02:09 Portugal
drwxr-xr-x  19 root root  4096 5月  27 12:56 posix/
-rw-r--r--   1 root root  3545 4月  21 02:09 posixrules
-rw-r--r--   1 root root   414 4月  21 02:09 PRC
-rw-r--r--   1 root root  2294 4月  21 02:09 PST8PDT
drwxr-xr-x  19 root root  4096 5月  27 12:56 right/
-rw-r--r--   1 root root   800 4月  21 02:09 ROC
-rw-r--r--   1 root root   571 4月  21 02:09 ROK
-rw-r--r--   1 root root   428 4月  21 02:09 Singapore
drwxr-xr-x   2 root root  4096 5月  27 12:56 SystemV/
-rw-r--r--   1 root root  2747 4月  21 02:09 Turkey
-rw-r--r--   1 root root   127 4月  21 02:09 UCT
lrwxrwxrwx   1 root root     4 5月  27 09:07 Universal -> Zulu
drwxr-xr-x   2 root root  4096 5月  27 12:56 US/
lrwxrwxrwx   1 root root     4 5月  27 09:07 UTC -> Zulu
-rw-r--r--   1 root root  1873 4月  21 02:09 WET
-rw-r--r--   1 root root  1528 4月  21 02:09 W-SU
-rw-r--r--   1 root root 17533 4月  13 16:01 zone1970.tab
-rw-r--r--   1 root root 19014 4月  13 16:01 zone.tab
-rw-r--r--   1 root root   127 4月  21 02:09 Zulu

方式2: mysql.time_zone_name表

> SELECT * FROM mysql.time_zone_name;
Name                            |Time_zone_id|
--------------------------------+------------+
Africa/Abidjan	37
Africa/Accra	159
Africa/Addis_Ababa	499
Africa/Algiers	230
Africa/Asmara	191
Africa/Asmera	590
Africa/Bamako	150
Africa/Bangui	256
Africa/Banjul	154
Africa/Bissau	26
Africa/Blantyre	329
Africa/Brazzaville	567
Africa/Bujumbura	94
Africa/Cairo	359
Africa/Casablanca	474
Africa/Ceuta	479
Africa/Conakry	216
Africa/Dakar	489
Africa/Dar_es_Salaam	353
Africa/Djibouti	449
Africa/Douala	368
Africa/Freetown	24
Africa/Gaborone	533
Africa/Harare	148
Africa/Johannesburg	455
Africa/Juba	49
Africa/Kampala	346
Africa/Khartoum	358
Africa/Kigali	564
Africa/Kinshasa	180
Africa/Lagos	574
Africa/Libreville	22
Africa/Lome	559
Africa/Luanda	356
Africa/Lubumbashi	269
Africa/Lusaka	204
Africa/Malabo	162
Africa/Maputo	524
Africa/Maseru	9
Africa/Mbabane	174
Africa/Mogadishu	492
Africa/Monrovia	480
Africa/Nairobi	145
Africa/Ndjamena	232
Africa/Niamey	471
Africa/Nouakchott	476
Africa/Ouagadougou	295
Africa/Porto-Novo	286
Africa/Sao_Tome	90
Africa/Timbuktu	363
Africa/Tripoli	304
Africa/Tunis	534
Africa/Windhoek	226
America/Adak	257
America/Anchorage	587
America/Anguilla	539
America/Antigua	258
America/Araguaina	32
America/Argentina/Buenos_Aires	52
America/Argentina/Catamarca	552
America/Argentina/ComodRivadavia	170
America/Argentina/Cordoba	225
America/Argentina/Jujuy	313
America/Argentina/La_Rioja	260
America/Argentina/Mendoza	578
America/Argentina/Rio_Gallegos	141
America/Argentina/Salta	320
America/Argentina/San_Juan	372
America/Argentina/San_Luis	58
America/Argentina/Tucuman	219
America/Argentina/Ushuaia	186
America/Aruba	67
America/Asuncion	429
America/Atikokan	11
America/Atka	21
America/Bahia	293
America/Bahia_Banderas	374
America/Barbados	547
America/Belem	89
America/Belize	160
America/Blanc-Sablon	405
America/Boa_Vista	385
America/Bogota	190
America/Boise	116
America/Buenos_Aires	6
America/Cambridge_Bay	355
America/Campo_Grande	462
America/Cancun	500
America/Caracas	195
America/Catamarca	137
America/Cayenne	488
America/Cayman	350
America/Chicago	194
America/Chihuahua	139
America/Coral_Harbour	23
America/Cordoba	365
America/Costa_Rica	239
America/Creston	319
America/Cuiaba	203
America/Curacao	354
America/Danmarkshavn	125
America/Dawson	498
America/Dawson_Creek	463
America/Denver	529
America/Detroit	332
America/Dominica	285
America/Edmonton	161
America/Eirunepe	127
America/El_Salvador	45
America/Ensenada	79
America/Fortaleza	491
America/Fort_Nelson	20
America/Fort_Wayne	123
America/Glace_Bay	531
America/Godthab	522
America/Goose_Bay	420
America/Grand_Turk	568
America/Grenada	336
America/Guadeloupe	117
America/Guatemala	88
America/Guayaquil	235
America/Guyana	439
America/Halifax	5
America/Havana	504
America/Hermosillo	233
America/Indiana/Indianapolis	259
America/Indiana/Knox	553
America/Indiana/Marengo	478
America/Indiana/Petersburg	338
America/Indiana/Tell_City	310
America/Indiana/Vevay	545
America/Indiana/Vincennes	337
America/Indiana/Winamac	361
America/Indianapolis	70
America/Inuvik	503
America/Iqaluit	523
America/Jamaica	411
America/Jujuy	364
America/Juneau	283
America/Kentucky/Louisville	290
America/Kentucky/Monticello	496
America/Knox_IN	484
America/Kralendijk	375
America/La_Paz	199
America/Lima	390
America/Los_Angeles	418
America/Louisville	106
America/Lower_Princes	446
America/Maceio	421
America/Managua	247
America/Manaus	131
America/Marigot	445
America/Martinique	40
America/Matamoros	217
America/Mazatlan	399
America/Mendoza	165
America/Menominee	238
America/Merida	86
America/Metlakatla	525
America/Mexico_City	78
America/Miquelon	15
America/Moncton	107
America/Monterrey	589
America/Montevideo	333
America/Montreal	289
America/Montserrat	322
America/Nassau	119
America/New_York	276
America/Nipigon	12
America/Nome	571
America/Noronha	228
America/North_Dakota/Beulah	138
America/North_Dakota/Center	542
America/North_Dakota/New_Salem	518
America/Nuuk	234
America/Ojinaga	520
America/Panama	231
America/Pangnirtung	250
America/Paramaribo	266
America/Phoenix	202
America/Port-au-Prince	348
America/Porto_Acre	113
America/Porto_Velho	475
America/Port_of_Spain	301
America/Puerto_Rico	80
America/Punta_Arenas	423
America/Rainy_River	344
America/Rankin_Inlet	132
America/Recife	193
America/Regina	71
America/Resolute	543
America/Rio_Branco	129
America/Rosario	464
America/Santarem	114
America/Santa_Isabel	18
America/Santiago	51
America/Santo_Domingo	408
America/Sao_Paulo	441
America/Scoresbysund	126
America/Shiprock	334
America/Sitka	431
America/St_Barthelemy	108
America/St_Johns	585
America/St_Kitts	227
America/St_Lucia	28
America/St_Thomas	394
America/St_Vincent	210
America/Swift_Current	318
America/Tegucigalpa	112
America/Thule	105
America/Thunder_Bay	413
America/Tijuana	556
America/Toronto	291
America/Tortola	582
America/Vancouver	144
America/Virgin	299
America/Whitehorse	314
America/Winnipeg	483
America/Yakutat	573
America/Yellowknife	209
Antarctica/Casey	102
Antarctica/Davis	93
Antarctica/DumontDUrville	551
Antarctica/Macquarie	509
Antarctica/Mawson	2
Antarctica/McMurdo	109
Antarctica/Palmer	452
Antarctica/Rothera	60
Antarctica/South_Pole	297
Antarctica/Syowa	409
Antarctica/Troll	461
Antarctica/Vostok	468
Arctic/Longyearbyen	56
Asia/Aden	176
Asia/Almaty	554
Asia/Amman	422
Asia/Anadyr	275
Asia/Aqtau	155
Asia/Aqtobe	486
Asia/Ashgabat	527
Asia/Ashkhabad	481
Asia/Atyrau	64
Asia/Baghdad	218
Asia/Bahrain	526
Asia/Baku	437
Asia/Bangkok	465
Asia/Barnaul	442
Asia/Beijing	31
Asia/Beirut	140
Asia/Bishkek	316
Asia/Brunei	550
Asia/Calcutta	309
Asia/Chita	220
Asia/Choibalsan	404
Asia/Chongqing	224
Asia/Chungking	187
Asia/Colombo	347
Asia/Dacca	448
Asia/Damascus	540
Asia/Dhaka	27
Asia/Dili	173
Asia/Dubai	341
Asia/Dushanbe	252
Asia/Famagusta	163
Asia/Gaza	548
Asia/Harbin	370
Asia/Hebron	223
Asia/Hong_Kong	55
Asia/Hovd	124
Asia/Ho_Chi_Minh	146
Asia/Irkutsk	466
Asia/Istanbul	398
Asia/Jakarta	450
Asia/Jayapura	243
Asia/Jerusalem	516
Asia/Kabul	264
Asia/Kamchatka	240
Asia/Karachi	157
Asia/Kashgar	39
Asia/Kathmandu	340
Asia/Katmandu	433
Asia/Khandyga	74
Asia/Kolkata	8
Asia/Krasnoyarsk	41
Asia/Kuala_Lumpur	236
Asia/Kuching	43
Asia/Kuwait	214
Asia/Macao	560
Asia/Magadan	97
Asia/Makassar	430
Asia/Manila	362
Asia/Muscat	298
Asia/Nicosia	253
Asia/Novokuznetsk	151
Asia/Novosibirsk	561
Asia/Omsk	254
Asia/Oral	175
Asia/Phnom_Penh	246
Asia/Pontianak	328
Asia/Pyongyang	339
Asia/Qatar	248
Asia/Qostanay	415
Asia/Qyzylorda	513
Asia/Rangoon	360
Asia/Riyadh	75
Asia/Saigon	103
Asia/Sakhalin	424
Asia/Samarkand	287
Asia/Seoul	570
Asia/Shanghai	130
Asia/Singapore	321
Asia/Srednekolymsk	395
Asia/Taipei	490
Asia/Tashkent	323
Asia/Tbilisi	366
Asia/Tehran	565
Asia/Tel_Aviv	460
Asia/Thimbu	327
Asia/Thimphu	158
Asia/Tokyo	400
Asia/Tomsk	91
Asia/Ujung_Pandang	100
Asia/Ulaanbaatar	343
Asia/Ulan_Bator	249
Asia/Urumqi	335
Asia/Ust-Nera	537
Asia/Vientiane	212
Asia/Vladivostok	538
Asia/Yakutsk	427
Asia/Yangon	82
Asia/Yekaterinburg	98
Asia/Yerevan	198
Atlantic/Azores	515
Atlantic/Bermuda	99
Atlantic/Canary	1
Atlantic/Cape_Verde	111
Atlantic/Faeroe	237
Atlantic/Faroe	485
Atlantic/Jan_Mayen	192
Atlantic/Madeira	172
Atlantic/Reykjavik	432
Atlantic/South_Georgia	456
Atlantic/Stanley	393
Atlantic/St_Helena	546
Australia/ACT	470
Australia/Adelaide	351
Australia/Brisbane	506
Australia/Broken_Hill	200
Australia/Canberra	566
Australia/Currie	101
Australia/Darwin	312
Australia/Eucla	519
Australia/Hobart	281
Australia/LHI	211
Australia/Lindeman	184
Australia/Lord_Howe	371
Australia/Melbourne	7
Australia/North	473
Australia/NSW	121
Australia/Perth	447
Australia/Queensland	555
Australia/South	311
Australia/Sydney	169
Australia/Tasmania	378
Australia/Victoria	153
Australia/West	406
Australia/Yancowinna	444
Brazil/Acre	296
Brazil/DeNoronha	245
Brazil/East	376
Brazil/West	407
Canada/Atlantic	511
Canada/Central	572
Canada/Eastern	417
Canada/Mountain	349
Canada/Newfoundland	17
Canada/Pacific	128
Canada/Saskatchewan	135
Canada/Yukon	507
CET	396
Chile/Continental	458
Chile/EasterIsland	68
CST6CDT	279
Cuba	389
EET	369
Egypt	580
Eire	386
EST	562
EST5EDT	453
Etc/GMT	280
Etc/GMT+0	50
Etc/GMT+1	10
Etc/GMT+10	435
Etc/GMT+11	434
Etc/GMT+12	401
Etc/GMT+2	44
Etc/GMT+3	38
Etc/GMT+4	65
Etc/GMT+5	14
Etc/GMT+6	13
Etc/GMT+7	54
Etc/GMT+8	4
Etc/GMT+9	3
Etc/GMT-0	535
Etc/GMT-1	377
Etc/GMT-10	268
Etc/GMT-11	267
Etc/GMT-12	270
Etc/GMT-13	403
Etc/GMT-14	271
Etc/GMT-2	380
Etc/GMT-3	379
Etc/GMT-4	382
Etc/GMT-5	381
Etc/GMT-6	384
Etc/GMT-7	383
Etc/GMT-8	373
Etc/GMT-9	505
Etc/GMT0	262
Etc/Greenwich	136
Etc/UCT	133
Etc/Universal	352
Etc/UTC	583
Etc/Zulu	528
Europe/Amsterdam	29
Europe/Andorra	387
Europe/Astrakhan	288
Europe/Athens	345
Europe/Belfast	282
Europe/Belgrade	402
Europe/Berlin	85
Europe/Bratislava	274
Europe/Brussels	53
Europe/Bucharest	428
Europe/Budapest	416
Europe/Busingen	147
Europe/Chisinau	95
Europe/Copenhagen	118
Europe/Dublin	414
Europe/Gibraltar	367
Europe/Guernsey	57
Europe/Helsinki	581
Europe/Isle_of_Man	177
Europe/Istanbul	221
Europe/Jersey	87
Europe/Kaliningrad	397
Europe/Kiev	412
Europe/Kirov	201
Europe/Lisbon	215
Europe/Ljubljana	242
Europe/London	292
Europe/Luxembourg	255
Europe/Madrid	48
Europe/Malta	182
Europe/Mariehamn	179
Europe/Minsk	47
Europe/Monaco	477
Europe/Moscow	30
Europe/Nicosia	557
Europe/Oslo	110
Europe/Paris	300
Europe/Podgorica	229
Europe/Prague	120
Europe/Riga	171
Europe/Rome	482
Europe/Samara	265
Europe/San_Marino	514
Europe/Sarajevo	467
Europe/Saratov	35
Europe/Simferopol	326
Europe/Skopje	588
Europe/Sofia	577
Europe/Stockholm	61
Europe/Tallinn	307
Europe/Tirane	42
Europe/Tiraspol	143
Europe/Ulyanovsk	241
Europe/Uzhgorod	152
Europe/Vaduz	584
Europe/Vatican	325
Europe/Vienna	451
Europe/Vilnius	487
Europe/Volgograd	149
Europe/Warsaw	96
Europe/Zagreb	166
Europe/Zaporozhye	181
Europe/Zurich	510
GB	59
GB-Eire	134
GMT	46
GMT+0	213
GMT-0	575
GMT0	178
Greenwich	164
Hongkong	303
HST	197
Iceland	222
Indian/Antananarivo	426
Indian/Chagos	530
Indian/Christmas	208
Indian/Cocos	115
Indian/Comoro	586
Indian/Kerguelen	357
Indian/Mahe	308
Indian/Maldives	294
Indian/Mauritius	81
Indian/Mayotte	244
Indian/Reunion	392
Iran	457
Jamaica	342
Japan	438
Kwajalein	443
Libya	122
MET	517
Mexico/BajaNorte	563
Mexico/BajaSur	569
Mexico/General	278
MST	196
MST7MDT	330
Navajo	69
NZ	493
NZ-CHAT	251
Pacific/Apia	63
Pacific/Auckland	410
Pacific/Bougainville	532
Pacific/Chatham	168
Pacific/Chuuk	73
Pacific/Easter	331
Pacific/Efate	501
Pacific/Enderbury	104
Pacific/Fakaofo	83
Pacific/Fiji	62
Pacific/Funafuti	76
Pacific/Galapagos	188
Pacific/Gambier	502
Pacific/Guadalcanal	206
Pacific/Guam	508
Pacific/Honolulu	391
Pacific/Johnston	36
Pacific/Kiritimati	536
Pacific/Kosrae	472
Pacific/Kwajalein	541
Pacific/Majuro	34
Pacific/Marquesas	272
Pacific/Midway	419
Pacific/Nauru	591
Pacific/Niue	189
Pacific/Norfolk	277
Pacific/Noumea	459
Pacific/Pago_Pago	66
Pacific/Palau	156
Pacific/Pitcairn	315
Pacific/Pohnpei	440
Pacific/Ponape	436
Pacific/Port_Moresby	92
Pacific/Rarotonga	284
Pacific/Saipan	33
Pacific/Samoa	425
Pacific/Tahiti	261
Pacific/Tarawa	497
Pacific/Tongatapu	306
Pacific/Truk	72
Pacific/Wake	302
Pacific/Wallis	19
Pacific/Yap	16
Poland	558
Portugal	142
PRC	324
PST8PDT	167
ROK	388
Singapore	25
Turkey	183
UCT	544
Universal	84
US/Alaska	521
US/Aleutian	469
US/Arizona	512
US/Central	273
US/East-Indiana	454
US/Eastern	494
US/Hawaii	576
US/Indiana-Starke	205
US/Michigan	549
US/Mountain	77
US/Pacific	207
US/Pacific-New	317
US/Samoa	185
UTC	263
W-SU	495
WET	305
Zulu	579

数据库变量

• 查询时区配置

> show variables like '%time_zone%'; 
Variable_name   |Value |
----------------+------+
system_time_zone|+08   |
time_zone       |SYSTEM|


> SELECT @@GLOBAL.system_time_zone, @@GLOBAL.time_zone, @@SESSION.time_zone;
@@GLOBAL.system_time_zone|@@GLOBAL.time_zone|@@SESSION.time_zone|
-------------------------+------------------+-------------------+
+08                      |SYSTEM            |+00:00             |

system_time_zone

• 定义：

system_time_zone 是 MySQL 服务器的系统时区，即操作系统的本地时区。
这个变量反映了操作系统当前设置的时区名称，例如 UTC, CST, PST 等。

• 特点：

只读变量：system_time_zone 是只读的，你不能在 MySQL 中直接修改它。
设置时间：该变量的值是在 MySQL 服务器启动时从操作系统中获取的，并且在服务器运行期间不会改变。
用途：主要用于初始化 time_zone 变量的默认值。

• 查看方式

SELECT @@system_time_zone; -- SELECT @@GLOBAL.system_time_zone

或

SHOW VARIABLES LIKE '%time_zone%'

time_zone

• 定义：

time_zone 是 MySQL 中会话级别和全局级别的【时区设置】，控制 MySQL 如何将时间存储在 TIMESTAMP 类型字段中，以及如何将其展示给用户。

• 特点

可修改：time_zone 可以根据需要在全局或会话级别设置。全局时区设置影响所有连接，而会话时区设置仅影响当前连接。
默认值：在服务器启动时，time_zone 默认初始化为 system_time_zone 的值，除非你在配置文件（my.cnf 或 my.ini）中显式设置了它。
会话级别控制：在一个连接中，你可以使用 SET time_zone 命令来设置当前会话的时区。

• 与system_time_zone 数据库变量的关系

• 启动与初始化时：

当 MySQL 启动时，system_time_zone 反映操作系统的时区设置，time_zone 则初始化为与 system_time_zone 相同的值，除非在配置文件中设置了其他值。

• 系统与应用结合：
  system_time_zone 通常是固定的、仅可读的，由操作系统控制，适合服务器级别的操作。
  time_zone 则更多用于应用程序级别的操作、可修改的，允许在不同会话或用户之间使用不同的时区来处理时间数据。

• 时间操作与显示：

当你插入 TIMESTAMP 类型的数据时，MySQL 会将其转换为 UTC 存储，并根据当前的 time_zone 来显示它。
使用 time_zone 可以灵活地在不同的时区间转换时间数据，适应全球化应用的需求。

• 要知道mysql当前在什么时区，看哪个变量?

看 time_zone。不看 system_time_zone。
如要修改时区，直接修改 time_zone，无视 system_time_zone

• 查看（会话级、全局级）时区

> SELECT @@session.time_zone, @@global.time_zone;
@@session.time_zone|@@global.time_zone|
-------------------+------------------+
SYSTEM             |SYSTEM            |

• 支持全局修改

-- SQL 错误 [1227] [42000]: Access denied; you need (at least one of) the SUPER privilege(s) for this operation
set global time_zone = '+00:00'; -- or '+8:00' or 'Asia/Shanghai' -- 全局级

• 支持会话级修改

set time_zone = 'SYSTEM'; -- '+00:00' / '+08:00' / 'Asia/Shanghai'

JDBC URL时间时区参数: serverTimeZone/useJDBCCompliantTimezoneShift/useLegacyDatetimeCode

jdbc:mysql://172.xx.xx.xx:3306/test_db?serverTimezone=UTC&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&useUnicode=true&characterEncoding=gbk&useSSL=true

函数

FROM_UNIXTIME(...) : 受 time_zone 变量的影响

> set time_zone = '+08:00';
> select FROM_UNIXTIME(1617181920)
FROM_UNIXTIME(1617181920)|
-------------------------+
      2021-03-31 17:12:00|

> set time_zone = '+00:00';
> select FROM_UNIXTIME(1617181920)
FROM_UNIXTIME(1617181920)|
-------------------------+
      2021-03-31 17:12:00|  
FROM_UNIXTIME(1617181920)|
-------------------------+
      2021-03-31 09:12:00|

CURTIME() : 受 time_zone 变量的影响

> set time_zone = '+00:00';
> select CURTIME();
CURTIME()|
---------+
 12:29:58|

经试验，等效于 system_time_zone=+00 / time_zone=SYSTEM


> set time_zone = '+08:00';
> select CURTIME();
CURTIME()|
---------+
 20:29:58|

表字段

datetime(3) 类型

timestamp 类型

Y 推荐文献

• 获取时间 < [Linux] shell编程之基础篇 – 博客园/千千寰宇

X 参考文献

• GMT和UTC有什么区别？ – 虎牙视频

可直观地了解GMT和UTC的区别

• “GMT与UTC:全球时间的微妙差异” – 慕课网
• UTC时间、GMT时间、CST时间（北京时间）、时间戳 – CSDN

UTC时间、GMT时间、CST时间（北京时间）、时间戳
Linux 的时间操作
Spark SQL的时间操作

• MySQL中的system_time_zone和time_zone的比较 – CSDN
• system_time_zone << General << Forum List << MySQL Forums – mysql.com