如何将mysql表行转换为列-数据库问题

How to transpose mysql table rows into columns(如何将mysql表行转换为列)

本文介绍了如何将mysql表行转换为列的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

这是我当前的 mysql 表的样子:

Here is what my current mysql table looks like:

PunchID EmpID   PunchEvent  PunchDateTime
1       0456    clockin     5/14/2013 8:36:26 AM
48      0456    breakout    5/14/2013 12:01:29 PM
53      0456    breakin     5/14/2013 12:28:31 PM
54      0456    clockout    5/14/2013 2:28:33 PM
57      0456    clockin     5/15/2013 7:38:34 AM
58      0456    breakout    5/15/2013 7:38:39 AM
59      0456    breakin     5/15/2013 7:38:41 AM
60      0456    clockout    5/15/2013 7:38:42 AM

现在我想返回一个基于星期几分组的结果集，如下所示:

Now I want to return a result set that is grouped based on the day of the week like so:

Day       ClockIn      BreakOut    BreakIn      ClockOut
Tuesday   8:36:26 AM  12:01:29 PM  12:28:31 PM  2:28:33 PM
Wednesday 7:38:34 AM  etc, etc...

这是我当前的查询.但它只返回每天的第一拳.

This is my current query. But it only returns the first punch for each day.

SELECT DATE_FORMAT(PunchDateTime, '%W') as day, PunchEvent, DATE_FORMAT(PunchDateTime, '%l:%m:%s %p') as time FROM timeclock_punchlog WHERE EmpID = '0456' GROUP BY DATE(PunchDateTime) ORDER BY PunchDateTime ASC;

有人可以帮我解决这个问题吗?谢谢迈克

Can someone help me with this? Thanks Mike

推荐答案

SELECT  DATE_FORMAT(PunchDateTime, '%W') DAY,
        MAX(CASE WHEN PunchEvent = 'ClockIn' THEN DATE_FORMAT(PunchDateTime, '%r') END) ClockIn,
        MAX(CASE WHEN PunchEvent = 'BreakOut' THEN DATE_FORMAT(PunchDateTime, '%r') END) BreakOut,
        MAX(CASE WHEN PunchEvent = 'BreakIn' THEN DATE_FORMAT(PunchDateTime, '%r') END) BreakIn,
        MAX(CASE WHEN PunchEvent = 'ClockOut' THEN DATE_FORMAT(PunchDateTime, '%r') END) ClockOut
FROM    tableName
WHERE   EmpID = 456
GROUP   BY DATE_FORMAT(PunchDateTime, '%W')
ORDER   BY PunchDateTime

SQLFiddle 演示

输出

╔═══════════╦═════════════╦═════════════╦═════════════╦═════════════╗
║    DAY    ║   CLOCKIN   ║  BREAKOUT   ║   BREAKIN   ║  CLOCKOUT   ║
╠═══════════╬═════════════╬═════════════╬═════════════╬═════════════╣
║ Tuesday   ║ 08:36:26 AM ║ 12:01:29 PM ║ 12:28:31 PM ║ 02:28:33 PM ║
║ Wednesday ║ 07:38:34 AM ║ 07:38:39 AM ║ 07:38:41 AM ║ 07:38:42 AM ║
╚═══════════╩═════════════╩═════════════╩═════════════╩═════════════╝

这篇关于如何将mysql表行转换为列的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持编程学习网！