方法A：
SET @WEEK_NO = 40;
SET @_BD = '2014-12-29';
SET @_SD = DATE_FORMAT(DATE_ADD(@_BD, INTERVAL 7 * (@WEEK_NO - 1) DAY), '%Y%m%d');
SET @_ED = DATE_FORMAT(DATE_ADD(@_BD, INTERVAL 7 * @WEEK_NO - 1 DAY), '%Y%m%d');
SELECT @_SD, @_ED, DATE_FORMAT(@_SD, '%Y-%v周'), DATE_FORMAT(@_ED, '%Y-%v周')
方法二：
This would give you the Monday date of week 3 of 2010, which would be 2010-01-18.
Another example:
SELECT STR_TO_DATE('201052 Sunday', '%X%V %W');
Would give you the Sunday date of week 52 of 2010, which would be 2010-12-26.
And finally, using your original example:
SELECT STR_TO_DATE('201029 Sunday', '%X%V %W');
This gives 2010-07-18.