MySQL的高級加入

Question

我最近一直在學習MySQL和想知道如果有人可以幫助我解決這個問題我的工作..

我有兩個表，

首先是departmentTable

+------------+-----------+-----------+-----------+-----------+-----------+-----------+ 
| Department | Employee1 | Employee2 | Employee3 | Employee4 | Employee5 | Employee6 | 
+------------+-----------+-----------+-----------+-----------+-----------+-----------+ 
| Finance | Tim C  | Nora C | Susan P | Martin S | Donal D | Zita P | 
| HR   | Yvonne S | Marcus F | Mark B | Peter S | Ola G  | Gina P | 
| IT   | John W | Matt R | Paul M | Tom Y  | Jean S | Martin T | 
+------------+-----------+-----------+-----------+-----------+-----------+-----------+ 

二是employeeDetails表

+--------------+-------+------------+--------+ 
| EmployeeName | Shift | Employment | Salary | 
+--------------+-------+------------+--------+ 
| Donal D  | Night | Full  | 30000 | 
| Gina P  | Night | Part  | 21000 | 
| Jean S  | Night | Full  | 30000 | 
| John W  | Night | Full  | 24000 | 
| Marcus F  | Night | Full  | 21000 | 
| Mark B  | Day | Full  | 23000 | 
| Martin S  | Day | Full  | 23400 | 
| Martin T  | Day | Part  | 31000 | 
| Matt R  | Day | Full  | 22000 | 
| Nora C  | Day | Full  | 22000 | 
| Ola G  | Night | Full  | 21400 | 
| Paul M  | Day | Part  | 23000 | 
| Peter S  | Day | Part  | 25000 | 
| Susan P  | Day | Part  | 23000 | 
| Tim C  | Day | Full  | 24000 | 
| Tom Y  | Day | Full  | 23400 | 
| Yvonne S  | Day | Full  | 24000 | 
| Zita P  | Night | Part  | 31000 | 
+--------------+-------+------------+--------+ 

我試圖找到一種方法如果有可能查詢哪個部門有4天和2夜班員工。所以它應該輸出是這樣的..

+------------+-----------+-----------+-----------+-----------+-----------+-----------+ 
| Department | Employee1 | Employee2 | Employee3 | Employee4 | Employee5 | Employee6 | 
+------------+-----------+-----------+-----------+-----------+-----------+-----------+ 
| Finance | Tim C  | Nora C | Susan P | Martin S | Donal D | Zita P | 
| IT   | John W | Matt R | Paul M | Tom Y  | Jean S | Martin T | 
+------------+-----------+-----------+-----------+-----------+-----------+-----------+ 

任何幫助表示讚賞，我知道這是不是存儲數據並獲取他們最好的方式，但我想了解和學習更多關於MySQL的加入和計數。

Answer 1

你應該通過在一列中存儲員工來修復你的表結構。

雖這麼說，你可以試試這個：

select 
    d.* 
from departmentTable d 
join employeeDetails e on e.EmployeeName in (
    d.Employee1, d.Employee2, d.Employee3, 
    d.Employee4, d.Employee5, d.Employee6 
) 
group by d.department 
having sum(e.shift = 'Night') = 2 
and sum(e.shift = 'Day') = 4 

Answer 2

您應該使用一張表格，您可以在其中存儲所有員工的詳細信息並在其中添加引用某個部門的詳細信息。不要在employee1-n中使用你的方法。

另外，當我看到Nora C出現在兩個部門時，可能會看看m-n關係。 Google是你的朋友