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當他更改其狀態(日期,狀態,ID(FK))時,我有一張僱員(ID)和表的表。我需要顯示的員工列表排序按指定的日期查找參數並比較其他表中的日期,按參數排序
employees
ID, Name
1, Jack
2, Ralf
3, Jenny
changes
IDchange, Date, Status, ID
1, 2015-01-01, 2, 1 //Jack started in 2015-1-1 with status 2
2, 2015-03-01, 1, 2 //Ralf started in 2015-3-1 with status 1
3, 2015-04-01, 1, 3 //Jenny started in 2015-4-1 with status 1
4, 2015-08-01, 2, 2 //Ralf change status to 2 in 2015-8-1
5, 2015-10-01, 3, 2 //Ralf change status to 3 in 2015-10-1
6, 2016-04-01, 4, 1 //Jack change status to 4 in 2016-04-1
我試圖theese任何日期$ My_Date的狀態,但我不知道如何修復它爲所有的變化,它僅檢查最後日期變更
<?php
$sql2="SELECT *, Status
FROM employees s
JOIN (
SELECT MAX(Date) max_date, ID, Status
FROM changes sml
WHERE date <= '".$My_Date."'
GROUP BY ID
) sml ON (sml.ID = s.ID)
ORDER BY Status, Name ASC";
$result2 = MySQL_Query($sql2);
... ?>
謝謝,可以,小問題:我怎麼容易得到變更日期? – DaveMX
@DaveMX你是指什麼意思*更改日期*? –
是請更改日期 – DaveMX