Go、xorm 時區

import (
    "fmt"
    "time"

    _ "github.com/go-sql-driver/mysql"
    "xorm.io/xorm"
)

[Go 時區]
取得目前時區與跟UTC的偏移量

t := time.Now()
zone, offset := t.Zone()
fmt.Println(zone, offset) //CST 28800

轉換成指定時區的時間

now := time.Now()
fmt.Println(now) //2021-05-07 03:05:05.029289 +0800 CST m=+0.002740401

time_zone_1, err1 := time.LoadLocation("") //UTC
if err1 != nil {
    fmt.Println(err1)
}
fmt.Println(now.In(time_zone_1)) //2021-05-06 19:05:05.029289 +0000 UTC

time_zone_2, err2 := time.LoadLocation("Local") //Server環境的時區
if err2 != nil {
    fmt.Println(err2)
}
fmt.Println(now.In(time_zone_2)) //2021-05-07 03:05:05.029289 +0800 CST

time_zone_3, err3 := time.LoadLocation("America/Los_Angeles")
if err3 != nil {
    fmt.Println(err3)
}
fmt.Println(now.In(time_zone_3)) //2021-05-06 12:05:05.029289 -0700 PDT

time_zone_4 := time.FixedZone("test", 60*60*3) //自訂一個時區,名稱test, UTC+3
fmt.Println(now.In(time_zone_4))               //2021-05-06 22:05:05.029289 +0300 test

//time_zone_5, err5 := time.LoadLocation("Asia/Shanghai")
//time_zone_5, err5 := time.LoadLocation("Asia/Taipei")

[xorm 時區]
取得 xorm 的時區設定

fmt.Println(engine.TZLocation) //Local

設定 xorm 時區

engine.TZLocation, _ = time.LoadLocation("America/Los_Angeles")
fmt.Println(engine.TZLocation) //America/Los_Angeles

其他：

1. time.Time 類型的資料包含時區 
2. parseTime=true，將 DATE、DATETIME 型態的資料用 time.Time 表示。
   parseTime=false，將 DATE、DATETIME 型態的資料用 []byte/string 表示。

   //engine, err := xorm.NewEngine("....?charset=utf8&parseTime=false", connStr)
   sql := "select STR_TO_DATE('2003-12-31 01:02:03', '%Y-%m-%d %H:%i:%s') AS t"
   results, err := engine.Query(sql)
   fmt.Println("results :", results)
   fmt.Println("results t:", string(results[0]["t"]))
   //parseTime=true
   //results : [map[t:[50 48 48 51 45 49 50 45 51 49 84 48 49 58 48 50 58 48 51 90]]]
   //results t: 2003-12-31T01:02:03Z
   //parseTime=false
   //results : [map[t:[50 48 48 51 45 49 50 45 51 49 32 48 49 58 48 50 58 48 51]]]
   //results t: 2003-12-31 01:02:03
   
   sql = "select STR_TO_DATE('0000-00-00 00:00:00', '%Y-%m-%d %H:%i:%s') AS t"
   results, err = engine.Query(sql)
   fmt.Println("results :", results)
   fmt.Println("results t:", string(results[0]["t"]))
   //parseTime=true
   //results : [map[t:[48 48 48 49 45 48 49 45 48 49 84 48 48 58 48 48 58 48 48 90]]]
   //results t: 0001-01-01T00:00:00Z
   //parseTime=false
   //results : [map[t:[48 48 48 48 45 48 48 45 48 48 32 48 48 58 48 48 58 48 48]]]
   //results t: 0000-00-00 00:00:00

   
   
   

參考：

• https://stackoverflow.com/questions/34975007/how-can-i-extract-the-value-of-my-current-local-time-offset
  go - How can I extract the value of my current local time offset? - Stack Overflow
• https://syaning.github.io/go-pkgs/time/#location
  time | Go语言标准包解析
• https://studygolang.com/topics/2192
  golang积累-时间、时区、格式的使用  - Go语言中文网 - Golang中文社区
• https://books.studygolang.com/xorm/chapter-04/1.created.html
  创建时间Created · XORM操作指南
• https://www.w3schools.com/SQl/func_mysql_str_to_date.asp
  MySQL STR_TO_DATE() Function
• https://github.com/go-sql-driver/mysql#dsn-data-source-name
  GitHub - go-sql-driver/mysql: Go MySQL Driver is a MySQL driver for Go's (golang) database/sql package