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转自：http://bbs.csdn.net/topics/370096126
t_table有数据如下：
year Week
2011 2
2011 3
2011 4
2011 5
想知道2011年的第二周起始日期和结束日期是哪2个？
SELECT year, week, x.start, ADDDATE(x.start, 6) AS end FROM ( SELECT ADDDATE(jan1, (t.week - WEEK(jan1, 5)) * 7 - WEEKDAY(jan1)) AS start, year, week FROM (SELECT MAKEDATE(`year`, 1) AS jan1, year, week FROM t_table) t ) x;+------+------+------------+------------+| year | week | start | end |+------+------+------------+------------+| 2011 | 1 | 2011-01-03 | 2011-01-09 || 2011 | 2 | 2011-01-10 | 2011-01-16 || 2011 | 3 | 2011-01-17 | 2011-01-23 || 2011 | 52 | 2011-12-26 | 2012-01-01 |+------+------+------------+------------+标签：
原文地址：http://www.cnblogs.com/bigben0123/p/5754138.html
