(Les16 Managing Data in Different Time Zones)[20171230]

學習目標： -current_date 當前時間 TZ_OFFSET -current_timestamp 含小數秒當前時間 FROM_TZ -localtimestamp 含小數秒本地時間 TO_TIMESTAMP -dbtimezone 資料庫時區 TO_TIMSTAMP_TZ -session ...

學習目標： -current_date 當前時間 TZ_OFFSET -current_timestamp 含小數秒當前時間 FROM_TZ -localtimestamp 含小數秒本地時間 TO_TIMESTAMP -dbtimezone 資料庫時區 TO_TIMSTAMP_TZ -sessiontimezone 回話時間時區 TO_YMINTERVAL -extract 提取 TO_DSINTERVAL TIME_ZONE會話參數可以設定為以下值 -一個絕對偏移值 -資料庫時區 -系統本地時區 -一個區功能變數名稱稱 ALTER SESSION SET TIME_ZONE = '-06:00'; ALTER SESSION SET TIME_ZONE = dbtimezone; ALTER SESSION SET TIME_ZONE = local; ALTER SESSION SET TIME_ZONE = 'America/New_York';

SYS@cqoraxt0>ALTER SESSION SET TIME_ZONE = dbtimezone;
Session altered.
SYS@cqoraxt0>select systimestamp from dual;
SYSTIMESTAMP
---------------------------------------------------------------------------
29-DEC-17 10.50.13.546588 PM +08:00 ->當前資料庫所在時區的時間
SYS@cqoraxt0>select localtimestamp from dual;
LOCALTIMESTAMP
---------------------------------------------------------------------------
29-DEC-17 02.50.38.464141 PM
SYS@cqoraxt0>ALTER SESSION SET TIME_ZONE = dbtimezone;
Session altered.
SYS@cqoraxt0>select localtimestamp from dual;
LOCALTIMESTAMP
---------------------------------------------------------------------------
29-DEC-17 02.50.49.337510 PM
SYS@cqoraxt0>ALTER SESSION SET TIME_ZONE = '-06:00';
Session altered.
SYS@cqoraxt0>select localtimestamp from dual;
LOCALTIMESTAMP
---------------------------------------------------------------------------
29-DEC-17 08.51.00.307601 AM->絕對偏移量的時區
SYS@cqoraxt0>ALTER SESSION SET TIME_ZONE = local;
Session altered.
SYS@cqoraxt0>select localtimestamp from dual;
LOCALTIMESTAMP
---------------------------------------------------------------------------
29-DEC-17 10.51.11.989536 PM->系統本地時間時區
SYS@cqoraxt0>ALTER SESSION SET TIME_ZONE = 'America/New_York';
Session altered.
SYS@cqoraxt0>select localtimestamp from dual;
LOCALTIMESTAMP
---------------------------------------------------------------------------
29-DEC-17 09.51.21.599491 AM ->指定時間區功能變數名稱稱

　　CURRENT_DATE,CURRENT_TIMESTAMP,LOCALTIMESTAMP -CURRENT_DATE 當前時間同sysdate表達一樣 -CURRENT_TIMESTAMP 含時區　　　 -LOCALTIMESTAMP 不含時區　　　

col CURRENT_DATE format a30
            col SESSIONTIMEZONE format a20
            col CURRENT_TIMESTAMP format a40
            col LOCALTIMESTAMP format a40
            col sysdate format a30
            set linesize 300
            alter session set nls_date_format='YYYY-MM-DD HH24:MI:SS'; 
            --調整時間輸出的格式
            select sessiontimezone,current_date,current_timestamp,localtimestamp,sysdate from dual;
        
SESSIONTIMEZONE      CURRENT_DATE                   CURRENT_TIMESTAMP                        LOCALTIMESTAMP                           SYSDATE
-------------------- ------------------------------ ---------------------------------------- ---------------------------------------- ------------------------------
+08:00               2017-12-29 23:13:08            29-DEC-17 11.13.08.826336 PM +08:00      29-DEC-17 11.13.08.826336 PM             2017-12-29 23:13:08

DBTIMEZONE,SESSIONTIMEZONE -DBTIMEZONE 資料庫時區，也就是0時區 -SESSIONTIMEZONE 會話的當前時區

  
            col SESSIONTIMEZONE format a20
            col sysdate format a30
            set linesize 300
            alter session set nls_date_format='YYYY-MM-DD HH24:MI:SS'; 
            --調整時間輸出的格式
            select dbtimezone,sessiontimezone,sysdate from dual;
DBTIME SESSIONTIMEZONE      SYSDATE
------ -------------------- ------------------------------
+00:00 +08:00               2017-12-29 23:16:04

TIMESTAMP 時間類型 -TIMESTAMP [(fractional_seconds_precision)] 包含：年，月，天，小時，分鐘，秒，時區小時，時區分鐘 -TIMESTAMP [(fractional_seconds_precision)] WITH TIME ZONE -TIMESTAMP [(fractional_seconds_precision)] WITH LOCAL TIME ZONE

TIMESTAMP時間類型各個值的範圍

DATE,TIMESTAMP的不同點 -TIMESTAMP相比DATE多小數秒，時區小時和時區分鐘。

create table time_t01(
id number,
t_date date default sysdate,
t_timestamp timestamp default current_timestamp
)
/
insert into time_t01 values(1,default,default);
/
col t_date format a30
col t_timestamp format a40
set linesize 300
alter session set nls_date_format='YYYY-MM-DD HH24:MI:SS';
--調整會話輸出時時間格式
select * from time_t01;
 
        ID T_DATE                         T_TIMESTAMP
---------- ------------------------------ ----------------------------------------
         1 2017-12-29 23:51:55            29-DEC-17 11.51.55.085972 PM

--添加一個欄位
alter table time_t01 add (t_timestamp_zone timestamp with time zone);
 
insert into time_t01 values(2,default,default,timestamp'2017-12-29 23:57:00 +8:00');
commit;
insert into time_t01 values(3,default,default,timestamp'2017-12-29 23:57:00 America/New_York');
commit;
insert into time_t01 values(4,default,default,timestamp'2017-12-29 23:57:00 -8:00');
commit;
col t_timestamp_zone format a50
select * from time_t01;
        ID T_DATE                         T_TIMESTAMP                              T_TIMESTAMP_ZONE
---------- ------------------------------ ---------------------------------------- --------------------------------------------------
         1 2017-12-29 23:51:55            29-DEC-17 11.51.55.085972 PM
         2 2017-12-29 23:57:39            29-DEC-17 11.57.39.696414 PM             29-DEC-17 11.57.00.000000 PM +08:00
         3 2017-12-30 00:02:51            30-DEC-17 12.02.51.376596 AM             29-DEC-17 11.57.00.000000 PM AMERICA/NEW_YORK
         4 2017-12-30 00:02:51            30-DEC-17 12.02.51.385169 AM             29-DEC-17 11.57.00.000000 PM -08:00
 
  --添加一個欄位
 alter table time_t01 add (t_timestamp_local_zone timestamp with local time zone);
 insert into time_t01 values(5,default,default,current_timestamp,current_timestamp);
 col t_timestamp_local_zone format a50
 select * from time_t01 order by id;
                ID T_DATE                         T_TIMESTAMP                              T_TIMESTAMP_ZONE                                   T_TIMESTAMP_LOCAL_ZONE
---------- ------------------------------ ---------------------------------------- -------------------------------------------------- --------------------------------------------------
         1 2017-12-29 23:51:55            29-DEC-17 11.51.55.085972 PM
         2 2017-12-29 23:57:39            29-DEC-17 11.57.39.696414 PM             29-DEC-17 11.57.00.000000 PM +08:00
         3 2017-12-30 00:02:51            30-DEC-17 12.02.51.376596 AM             29-DEC-17 11.57.00.000000 PM AMERICA/NEW_YORK
         4 2017-12-30 00:02:51            30-DEC-17 12.02.51.385169 AM             29-DEC-17 11.57.00.000000 PM -08:00
         5 2017-12-30 00:07:05            30-DEC-17 12.07.05.688410 AM             30-DEC-17 12.07.05.688410 AM +08:00                30-DEC-17 12.07.05.688410 AM
        
 改變會話當前時區，timestamp with local time zone 時間也會跟著變動
 SYS@cqoraxt0>alter session set time_zone='-09:00';
 Session altered.
 SYS@cqoraxt0> select * from time_t01 order by id;
 
        ID T_DATE                         T_TIMESTAMP                              T_TIMESTAMP_ZONE                                   T_TIMESTAMP_LOCAL_ZONE
---------- ------------------------------ ---------------------------------------- -------------------------------------------------- --------------------------------------------------
         1 2017-12-29 23:51:55            29-DEC-17 11.51.55.085972 PM
         2 2017-12-29 23:57:39            29-DEC-17 11.57.39.696414 PM             29-DEC-17 11.57.00.000000 PM +08:00
         3 2017-12-30 00:02:51            30-DEC-17 12.02.51.376596 AM             29-DEC-17 11.57.00.000000 PM AMERICA/NEW_YORK
         4 2017-12-30 00:02:51            30-DEC-17 12.02.51.385169 AM             29-DEC-17 11.57.00.000000 PM -08:00
         5 2017-12-30 00:07:05            30-DEC-17 12.07.05.688410 AM             30-DEC-17 12.07.05.688410 AM +08:00                29-DEC-17 07.07.05.688410 AM

INTERVAL時間類型 -INTERVAL用於存儲兩個時間差 -年-月 Year-month INTERVAL YEAR TO MONTH -天-時間 Day-time INTERVAL DAY TO SECOND INTERVAL YEAR (year_precision) TO MONTH INTERVAL DAY (day_precision) TO SECOND (fractional_seconds_precision)

create table time_t02(
id number,
t_interval_y interval year to month,
t_interval_d interval day to second
)
/
insert into time_t02 values(1,'03-5' ,'05 12:00:00')
/
insert into time_t02 values(2,interval '04' year,interval '06 13:00:00' day to second )
/
insert into time_t02 values(3,interval '12' month,interval '07 14:00:00' day to second )
/
 
 
alter session set nls_date_format='YYYY-MM-DD HH24:MI:SS';
col t_interval_y format a30
col t_interval_d format a30
select * from time_t02;
 
        ID T_INTERVAL_Y                   T_INTERVAL_D
---------- ------------------------------ ------------------------------
         1 +03-05                         +05 12:00:00.000000
         2 +04-00                         +06 13:00:00.000000
         3 +01-00                         +06 13:00:00.000000

EXTRACT 提取時間 -可提取時間類型 EXTRACT ([YEAR] [MONTH][DAY] [HOUR] [MINUTE][SECOND] [TIMEZONE_HOUR] [TIMEZONE_MINUTE] [TIMEZONE_REGION] [TIMEZONE_ABBR] -年、月、天、小時、分鐘、秒、時區小時、時區分鐘、時區區域、時區縮寫

set linezie 600
col zone_region format a20
col zone_abbr format a20
select
    extract(year from t_timestamp_zone) year,
    extract(month from t_timestamp_zone) month,
    extract(day from t_timestamp_zone) day,
    extract(hour from t_timestamp_zone) hour,
    extract(minute from t_timestamp_zone) minute,
    extract(second from t_timestamp_zone) second,
    extract(timezone_hour from t_timestamp_zone) zone_hour,
    extract(timezone_minute from t_timestamp_zone) zone_minute,
    extract(timezone_region from t_timestamp_zone) zone_region,
    extract(timezone_abbr from t_timestamp_zone) zone_abbr
    from time_t01
where id=3
/
            
                  YEAR      MONTH        DAY       HOUR     MINUTE     SECOND  ZONE_HOUR ZONE_MINUTE
---------- ---------- ---------- ---------- ---------- ---------- ---------- -----------
ZONE_REGION          ZONE_ABBR
-------------------- --------------------
      2017         12         30          4         57          0         -5           0
America/New_York     EST

時區轉換函數 -TZ_OFFSET 時間區域轉為為數值 TZ_OFFSET ( ['time_zone_name'] '[+ | -] hh:mm' ] [ SESSIONTIMEZONE] [DBTIMEZONE]

SYS@cqoraxt0>select tz_offset('America/New_York') from dual;
TZ_OFFS
-------
-05:00

V$TIMEZONE_NAMES所有時區區功能變數名稱稱視圖 -FROM_TZ 將TIMESTAMP轉換為TIMESTAMP WITH TIME ZONE FROM_TZ(TIMESTAMP timestamp_value, time_zone_value)

SYS@cqoraxt0>select from_tz(timestamp '2017-12-30 23:50:00','+8:00') from dual;
FROM_TZ(TIMESTAMP'2017-12-3023:50:00','+8:00')
---------------------------------------------------------------------------
30-DEC-17 11.50.00.000000000 PM +08:00

-TO_TIMESTAMP 將字元串轉為TIMESTAMP時間類型 TO_TIMESTAMP (char,[fmt],['nlsparam'])

SYS@cqoraxt0>select to_timestamp('2017-12-30 23:53:00','YYYY-MM-DD HH24:MI:SS') from dual;
TO_TIMESTAMP('2017-12-3023:53:00','YYYY-MM-DDHH24:MI:SS')
---------------------------------------------------------------------------
30-DEC-17 11.53.00.000000000 PM

-TO_TIMESTAMP_TZ 將字元串轉為TIMESTAMP WITH TIME ZONE TO_TIMESTAMP_TZ (char,[fmt],['nlsparam'])

SYS@cqoraxt0>select to_timestamp_tz('2017-12-30 23:55:00 +8:00','YYYY-MM-DD HH24:MI:SS TZH:TZM') from dual;
           TO_TIMESTAMP_TZ('2017-12-3023:55:00+8:00','YYYY-MM-DDHH24:MI:SSTZH:TZM')
---------------------------------------------------------------------------
30-DEC-17 11.55.00.000000000 PM +08:00

-TO_YMINTERVAL 將字元串轉為時間間隔類型INTERVAL YEAR TO MONTH TO_YMINTERVAL(char)

 SYS@cqoraxt0>select sysdate+to_yminterval('01-01') from  dual;
SYSDATE+TO_YMINTERV
-------------------
2019-01-31 00:03:14

-TO_DSINTERVAL 將字元串轉為時間間隔類型INTERVAL DAY TO SECOND

TO_DSINTERVAL(char)

 SYS@cqoraxt0>select sysdate+to_dsinterval('05 1:00:00') from dual;
            SYSDATE+TO_DSINTERV
            -------------------
            2018-01-05 01:06:57

學習總結： 1.5個時間current_date、current_timestamp、localtimestamp、dbtimezone、sessionzone 2.時區值的更改及對應可選值資料庫時區、系統時區、偏移量值、時區區功能變數名稱稱 3.時間類型:DATE ,TIMESTAMP,TIMESTAMP WITH TIME ZONE ,TIMESTAMP WITH LOCAL TIME ZONE,INTERVAL YEAR TO MONTH,INTERVAL DAY TO SECOND 4.時間類型中的各個值的提取函數EXTRACT 5.時間類型的轉換函數TO_DATE,TZ_OFFSET,FROM_TZ,TO_TIMESTAMP,TO_TIMSTAMP_TZ,TO_YMINTERVAL,TO_DSINTERVAL