SQL查詢，不同的行所需

Question

嗨，我有以下表的結構是這樣的：

所以基本上你可以看到，該部門經過名稱變更每隔幾年。以數字16爲例。我想要一個選擇查詢，只有當日期最大時纔會獲得該名稱。我怎麼做？

Answer 1

select ID, Name from departments o 
where o.thedate= 
    (select max(i.thedate) from departments i where o.id=i.id) 

Answer 2

此表的主要關鍵是什麼？這可以通過名稱比較對同一個表進行子查詢。

SELECT 
    id, 
    name, 
    date 
FROM table 
WHERE name = (SELECT TOP 1 name 
       FROM table AS subtable 
       WHERE subtable.name = table.name 
       ORDER BY date DESC) 

Answer 3

SELECT ID, 
First(Name) AS FirstOfName, First(DateChange) AS FirstOfDateChange 
FROM departments 
GROUP BY ID 
ORDER BY First(DateChange) DESC; 

Answer 4

SELECT d。* FROM 部門ð INNER JOIN（SELECT PK FROM部門 GROUP BY ID HAVING theDate = MAX（theDate））M於m.pk = d .pk WHERE [Name] =「部門」