给定年，月，日和月的周数，我如何找到日期？

Question

我

Year : 2011 
Month: Nov 
Day: Sun 
WeekNumber(Monthwise): 4 

欲望输出：

Date 
-------- 
2011-11-20 

我怎么能在一个单独的SQL语句这样做呢？

感谢

Answer 1

我可能会看使用NEXT_DAY函数返回给定的日期之后发生提供平日的第一天。一旦你有了，你可以添加所需的周数。

这方面的一个例子是：

with test_data as (
    select 
    '2011' as the_year, 
    'Nov' as the_month, 
    'Sun' as the_day, 
    4 as the_week 
    from dual 
) 
select 
    the_year, the_month, the_day, the_week, 
    next_day(to_date(the_year||the_month, 'YYYYMON') - 1, the_day) + 
    7* (the_week -1) as the_date 
from test_data 

Answer 2

尝试：

SELECT A.B + B.D YourDate 
FROM (SELECT TO_DATE (Your4DigitYear || LPAD (YourMonth, 2, '0') || LPAD (DECODE (YourWeekOfMonth, 1, '1', (YourWeekOfMonth - 1) * 7), 2, '0'), 'YYYYMMDD') B FROM DUAL) A, (SELECT LEVEL - 1 D FROM DUAL CONNECT BY LEVEL < 15) B WHERE 
TO_CHAR (A.B + B.D, 'D') = YourDayOfWeek AND 
TO_CHAR (A.B + B.D, 'W') = YourWeekOfMonth; 

Answer 3

这可能工作。

SELECT NEXT_DAY(TO_DATE(TO_CHAR((4-1)*7) || '-' || 'NOV' || '-' || '2011','dd-mon-yyyy') ,'Sun') 
FROM DUAL 

见：http://download.oracle.com/docs/cd/B19306_01/server.102/b14200/functions093.htm