oracle 计算oracle中两个日期之间的周数
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To count the number of weeks between two dates in oracle
提问by renu
I have used the below query to find the number of weeks between two dates:
我使用以下查询来查找两个日期之间的周数：
select count(week_id)
from fw
where week_begin_date >= '2015-01-01'
and week_end_date <= '2015-12-31';
Expected result should be 53 but the actual result is 51.
预期结果应为 53，但实际结果为 51。
Kindly help on this.
请对此提供帮助。
回答by xQbert
Can't you just use the week of year function? subtract if needed...
你不能只使用一年中的一周功能吗？如果需要，减去...
select to_char(to_date('12/31/2015','MM/DD/YYYY'),'WW') from dual;
select To_Number(to_char(to_date('12/31/2015','MM/DD/YYYY'),'WW')) -
To_number(to_char(to_date('01/01/2015','MM/DD/YYYY'),'WW')) +1
from dual;
We have to add +1 because weeks start at 1 not 0.
我们必须加上 +1，因为周从 1 开始，而不是 0。
Now maybe you're after the ISO week format which would be IWinstead of WW.
现在也许你在追求 ISO 周格式，IW而不是WW.
WW:Week of year (1-53) where week 1 starts on the first day of the year and continues to the seventh day of the year.
WW：一年中的第几周 (1-53)，其中第 1 周从一年的第一天开始并持续到一年的第七天。
IW:Week of year (1-52 or 1-53) based on the ISO standard.
IW：基于 ISO 标准的一年中的第几周（1-52 或 1-53）。
回答by Asif Mehmood
Did you try this:
你试过这个吗：
SELECT
REPLACE((
to_date('20151231','yyyymmdd') - to_date('20150101','yyyymmdd')
)/7, '-', '')
FROM
DUAL
