从日期postgres中提取星期数 [英] extract week number from date postgres

问题描述

我想将周数提取为：

2015-52

，格式为：

2015-12-27

如何在postgres中执行此操作？

How can I perform this in postgres?

我的星期是从星期一到星期日计算的。

my weeks are calculated from monday to sunday.

推荐答案

字符值，请使用 to_char（）

To get the year and the week in a single character value, use to_char()

select to_char(current_date, 'IYYY-IW');

IW 返回年份和星期数为在ISO标准中定义的和 IYYY 返回相应的年份（可能是上一年）。

IW returns the year and the week number as defined in the ISO standard and IYYY returns the corresponding year (which might be the previous year).

如果需要以年和周为编号，请使用 提取

If you need the year and the week number as numbers, use extract

select extract('isoyear' from current_date) as year, 
       extract('week' from current_date) as week;

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