postgresql - 我想提取今天的日期，如果今天的日期是星期五，则执行 (today-3) else (today-11)

Question

我想提取今天的日期，如果今天是星期五，则执行 (today-3) else (today-11) 并在下面的删除语句中使用此查询的结果

这是我的查询:

Delete from table where date<(above result)

select now()::timestamp::date; this statement will give me the today's date
select to_char(now()::timestamp::date, 'dy') this will give me week day in string
select extract(dow from now()::timestamp) this will give me week day in integer

我怎样才能结合这些东西来实现我的要求。

Answer 1

你可以这样尝试:

select case extract(dow from current_date) when 5 
         then (CURRENT_DATE - INTERVAL '3 day') 
         else
         CURRENT_DATE - INTERVAL '11 day' end

SQLFIDDLE DEMO