Home Database Mysql Tutorial Oracle 使用 ROUND 和 EXTRACT 操作日期

Oracle 使用 ROUND 和 EXTRACT 操作日期

Jun 07, 2016 pm 05:12 PM

Oracle 使用 ROUND 和 EXTRACT 操作日期

Oracle 使用 ROUND 和 EXTRACT 操作日期:

ROUND(d,[fmt]):返回一个以 fmt 为格式的四舍五入日期值。

d 是日期,fmt 是格式模型,不能为时分秒。默认为 DDD,即月中的某一天。

  • 如果 fmt 为 “YEAR” 则舍入到某年的一月一日,即前半年舍去,后半年作为下一年。
  • 如果 fmt 为 “MONTH” 则舍入到某月的一日,即前半月舍去,,后半月作为下一月。
  • 如果 fmt 为 “DDD” 即月中的某一天,最靠近的天,前半天舍去,后半天作为第二天。
  • 如果 fmt 为 “DAY” 则舍入到最近的周的周日,即上半周舍去,下半周作为下一周周日。
  • EXTRACT(fmt FROM d):提取日期中的特定部分。

    fmt 为:YEAR、MONTH、DAY、HOUR、SECOND。其中 YEAR、MONTH、DAY 可以为 DATA 类型匹配,也可以与 TIMESTAMP 类型匹配;但是 HOUR、MINUTE、SECOND 必须与 TIMESTAMP 类型匹配。

    更多Oracle相关信息见Oracle 专题页面 ?tid=12

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