The DATE data type
The TIMESTAMP data types:
TIMESTAMP
TIMESTAMP WITH TIME ZONE
TIMESTAMP WITH LOCAL TIME ZONE
The INTERVAL data types:
INTERVAL YEAR TO MONTH
INTERVAL DAY TO SECOND
DATE类型包括日期和时间
TIMESTAMP的精度默认值是6,即6位的小数秒
INTERVAL 的YEAR精度默认值是2,DAY是2,SECOND是6
NUMTOYMINTERVAL函数可以将数字类型的值转换成INTERVAL YEAR TO MONTH类型,例如:NUMTOYMINTERVAL(2,'YEAR')
NUMTODSINTERVAL 函数可以将数字类型的值转换成INTERVAL DAY TO SECOND类型,例如:NUMTODSINTERVAL(5369.2589,'SECOND')
TO_DATE
TO_TIMESTAMP
TO_TIMESTAMP_TZ
TO_YMINTERVAL
TO_DSINTERVAL
NUMTOYMINTERVAL
NUMTODSINTERVAL
TO_CHAR
函数中的格式字符串默认格式由NLS_DATE_FORMAT, NLS_TIMESTAMP_FORMAT, NLS_TIMESTAMP_TZ 这几个参数决定,可以查询视图NLS_SESSION_PARAMETERS来获取这几个参数的值。
SELECT parameter, valueFROM nls_session_parametersWHERE parameter LIKE '%FORMAT';PARAMETER VALUE------------------------------ ------------------------------NLS_DATE_FORMAT DD-MON-RRNLS_TIME_FORMAT HH.MI.SSXFF AMNLS_TIMESTAMP_FORMAT DD-MON-RR HH.MI.SSXFF AMNLS_TIME_TZ_FORMAT HH.MI.SSXFF AM TZRNLS_TIMESTAMP_TZ_FORMAT DD-MON-RR HH.MI.SSXFF AM TZR
指定默认格式:ALTER SESSION SET NLS_DATE_FORMAT = 'MMDDYY';
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