Oracle查詢：如何從此查詢中取消多個結果？

Question

我有以下表格：

CLIENT 
- ID 
- NAME 
- USER 

ORDER 
- ID 
- DATE 
- CLIENT_ID 
- USER 

ORDER_LINE 
- ORDER_ID 
- LINE_ID 
- USER 

用戶現場跟蹤誰最後修改記錄的人。此外，每個訂單項可能會被不同的用戶修改。

我試圖找出來，給一個用戶，有什麼吩咐他們已經參與了。

select 
client.id, 
client.name, 
order.id, 
order.date, 
case 
    when order_line.user = :user then 'Line Item' 
    when order.user = :user then 'Order' 
    when client.user = :user then 'Client' 
end 
from 
order_line 
join order on order_id = order.id 
join client on order.client_id = client.id 
where 
order_line.user = :user 
or order.user = :user 
or client.user = :user 

問題是，用戶可能同時觸摸order和order_line表，所以我得到多個結果。添加select distinct不會有幫助，因爲case語句的結果在每種情況下都不相同。

有沒有辦法來重組查詢，所以我只有每個訂單得到一個結果？

case語句的結果是不是真的那麼重要 - 這將是很好，如果我能在別人摸兩個表，但只是「行項目」的情況下，得到「行項目，令」將確定。

Answer 1

我提出這個

這將顯示該用戶改變所有的訂單，如果他改變線項目，但不是行項目

SELECT client.id, 
     client.name, 
     order.id, 
     order.date 
    FROM  order 
     JOIN 
      client 
     ON client_id = client.id 
WHERE  order.USER = :USER 
     OR client.USER = :USER 
     OR :USER IN (SELECT USER 
         FROM ORDER_LINE OL 
         WHERE ORDER_LINE.ORDER_ID = ORDER.ID) 

Answer 2

Oracle是否已經GROUP_CONCAT（或相似）MySQL有？

select client_id, name, order_id, date, group_concat(what separator ', ') as changes 
from (
select 
client.id as client_id, 
client.name, 
order.id as order_id, 
order.date, 
case 
    when order_line.user = :user then 'Line Item' 
    when order.user = :user then 'Order' 
    when client.user = :user then 'Client' 
end as what 
from 
order_line 
join order on order_id = order.id 
join client on order.client_id = client.id 
where 
order_line.user = :user 
or order.user = :user 
or client.user = :user 
) as part1 
group by client_id, name, order_id, date; 

Answer 3

如何串聯的最後一列，並使用不同的，這樣的事情：

select distinct 
client.id, 
client.name, 
order.id, 
order.date, 
case when order_line.user = :user then 'Line Item ' else '' end || 
    case when order.user = :user then 'Order ' else '' end || 
    case when client.user = :user then 'Client ' else '' end 
from 
order_line 
join order on order_id = order.id 
join client on order.client_id = client.id 
where 
order_line.user = :user 
or order.user = :user 
or client.user = :user 

？

Answer 4

嘗試類似如下：

select client_id, 
     max(client_name), 
     order_id, 
     max(order_date), 
     max(Line_User), 
     max(Order_User), 
     max(Client_User) 
(select client.id client_id, 
     client.name client_name, 
     order.id order_id, 
     order.date order_date, 
     case when order_line.user = :user then 'Y' else 'N' end Line_User, 
     case when order.user = :user then 'Y' else 'N' end Order_User, 
     case when client.user = :user then 'Y' else 'N' end Client_User 
from order_line 
join order on order_id = order.id 
join client on order.client_id = client.id 
where order_line.user = :user or order.user = :user or client.user = :user) 
group by client_id, order_id;