Oracle SQL中'YYYY'和'RRRR'有什么区别 [英] What is the difference between 'YYYY' and 'RRRR' in Oracle SQL

问题描述

我在 SQL 中有 2 个查询:

I have 2 queries in SQL:

select trunc(to_date('27-Jul-1987'),'YYYY') FROM dual; 

和

select trunc(to_date('27-Jul-1987'),'RRRR') FROM dual; 

两者都给我相同的结果.'RRRR' 和 'YYYY' 有什么区别?

Both are giving me the same result. What is the difference between 'RRRR' and 'YYYY'?

推荐答案

YYYY 给出当前年份为 4 位数字.

YYYY gives the current year as 4 digits.

RRRR 格式意味着 00 到 49 范围内的 2 位数年份被假定为当前 世纪(即具有与当前年份相同的前两位数字)，并且以 50 到 99 给出的年份被假定在上一个 世纪.

RRRR format means 2-digit years in the range 00 to 49 are assumed to be in the current century (ie have the same first two digits as the current year), and years given as 50 through 99 are assumed to be in the previous century.

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