的MySQL從同一個表中選擇當前和以前的專欄

Question

我已經在一個表tbl以下幾列：

OrderID:  Parent:  Child: 
    1    1   1 
    2    2   1 
    3    1   2 
    4    1   1 
    5    2   1 

我想獲得的電流（OrderID，Parent，Child）和LOWER (OrderID,Parent,Child) WHERE親子等於當前的OrderID的Parent和Child。

因此，舉例來說，如果我有OrderID=4結果應該是一個查詢如下：

OrderID: Parent: Child: 
4   1   1 
1   1   1 

和if OrderID=5

OrderID: Parent: Child: 
5   2   1 
2   2   1 

BTW，我可以做到這一點在PHP，但我想在單個查詢中執行。

Answer 1

好的，謝謝你的回覆，但我有我自己的答案。

SELECT a.OrderID,a.Parent,a.Child FROM tbl a 
JOIN (SELECT OrderID,Parent,Child FROM tbl WHERE OrderID={$OrderID}) b 
ON a.Parent=b.Parent 
AND a.Child=b.Child 
WHERE a.OrderId<=b.OrderID 
ORDER BY OrderID 
DESC LIMIT 2 

Answer 2

這將這樣的伎倆：

SELECT * 
FROM tbl 
WHERE Parent = (SELECT Parent FROM tbl WHERE OrderID = 4) 
    AND Child = (SELECT Child FROM tbl WHERE OrderID = 4) 

而且PHP內取行到一個數組，搜索您的訂單ID，並得到其前一個。

Answer 3

SELECT * FROM FROM Orders WHERE OrderID = 4 
UNION ALL 
SELECT * FROM FROM Orders WHERE Parent = 4 ORDER BY OrderID DESC Limit 1 

此外，如果你有時間看看我的這個答案會給你一個很好的示範。

Finding free blocks of time in mysql and php?

Answer 4

SELECT * FROM FROM Orders WHERE OrderID = @orderId 
UNION ALL 
SELECT * FROM FROM Orders WHERE Parent = @orderId 

Answer 5

你可以做這樣的事情：

(SELECT OrderID, Parent, Child 
FROM tbl 
WHERE OrderID = 4) 
UNION 
(SELECT OrderID, Parent, Child 
FROM tbl 
WHERE Parent = (SELECT Parent FROM tbl WHERE OrderID = 4) 
    AND Child = (SELECT Child FROM tbl WHERE OrderID = 4) 
ORDER BY OrderID ASC LIMIT 1) 

我不知道這樣做的性能雖然...

Answer 6

這對我的作品。

select B.* from 
    (select A.Parent,A.Child from `tbl` A 
    where A.OrderID = 4) C 
    inner join `tbl` B 
on C.Parent = B.Parent 
and C.Child = B.Child 
order by B.OrderID desc