如何从MySQL中找到最新的周和月

时间:2012-11-03 13:36:52

标签: mysql

This DEMO按月显示。 this DEMO按周显示。但是我想要显示

Q1:每个学生只有本周。

第二季度:每个学生只有这个月。

问题3:每个学生上周才开始。

第四季度:每个学生只有上个月。

我怎样才能做到这一点?

CREATE TABLE `hw_homework` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `studentid` int(10) NOT NULL,
  `subjectid` int(10) NOT NULL,
  `assignment_name` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
  `teacherid` int(10) NOT NULL,
  `date` datetime NOT NULL,
  PRIMARY KEY (`id`)
) ;

INSERT INTO `hw_homework` (`id`, `studentid`, `subjectid`, `assignment_name`, `teacherid`, `date`) VALUES
(1, 29, 5, '5E', 20, '2012-10-31 13:58:40'),
(2, 15, 5, '32B', 20, '2012-10-31 13:59:54'),
(3, 29, 4, 'Q2A', 20, '2012-10-30 17:53:46'),
(4, 29, 11, '6E', 20, '2012-10-02 20:06:39'),
(5, 29, 11, 'C15', 20, '2012-10-16 20:06:30'),
(6, 15, 11, '7A', 20, '2012-09-19 20:08:05'),
(7, 29, 5, '3B', 20, '2012-09-14 20:08:12'),
(8, 29, 13, '6E', 32, '2012-10-29 20:23:46'),
(9, 29, 11, '7E', 18, '2012-10-30 14:35:14'),
(10, 2, 5, '5E', 20, '2012-10-21 13:58:40'),
(11, 2, 5, '5E', 20, '2012-10-30 13:58:40'),
(12, 2, 5, '5E', 20, '2012-10-31 13:58:40');

按月计算

SELECT  studentID, 
        DATE_FORMAT(`date`, '%M') `month`,
        COUNT(studentID) totalMissed
FROM hw_homework
-- WHERE studentID = ''
GROUP BY studentID, DATE_FORMAT(`date`, '%M')

按周计算

SELECT  studentID, 
        DATE_FORMAT(`date`, '%U') `WeekNo`,
        COUNT(studentID) totalMissed
FROM hw_homework
-- WHERE studentID = ''
GROUP BY studentID, DATE_FORMAT(`date`, '%U')

提前致谢。

1 个答案:

答案 0 :(得分:1)

A1

SELECT  studentID, 
        DATE_FORMAT(`date`, '%U') `WeekNo`,
        COUNT(studentID) totalMissed
FROM hw_homework
WHERE DATE_FORMAT(`date`, '%U') = DATE_FORMAT(NOW(), '%U')
-- AND studentID = ''
GROUP BY studentID, DATE_FORMAT(`date`, '%U')

A2

SELECT  studentID, 
        DATE_FORMAT(`date`, '%M') `WeekNo`,
        COUNT(studentID) totalMissed
FROM hw_homework
WHERE DATE_FORMAT(`date`, '%M') = DATE_FORMAT(NOW(), '%M')
-- AND studentID = ''
GROUP BY studentID, DATE_FORMAT(`date`, '%M')

A3

SELECT  studentID, 
        DATE_FORMAT(`date`, '%U') `WeekNo`,
        COUNT(studentID) totalMissed
FROM hw_homework he
WHERE DATE_FORMAT(`date`, '%U') = (SELECT MAX(DATE_FORMAT(NOW(), '%U')) FROM hw_homework hi WHERE hi.studentID = he.studentID)
-- AND studentID = ''
GROUP BY studentID, DATE_FORMAT(`date`, '%U')

A4

SELECT  studentID, 
        DATE_FORMAT(`date`, '%M') `WeekNo`,
        COUNT(studentID) totalMissed
FROM hw_homework he
WHERE DATE_FORMAT(`date`, '%M') = (SELECT MAX(DATE_FORMAT(NOW(), '%M')) FROM hw_homework hi WHERE hi.studentID = he.studentID)
-- AND studentID = ''
GROUP BY studentID, DATE_FORMAT(`date`, '%M')