Question

我在表tbl中有以下列：

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

我想获得当前（OrderID，Parent，Child）和LOWER (OrderID,Parent,Child) WHERE父级和子级等于当前OrderID的父级和子级。< / p>

因此，例如，如果我对OrderID=4有查询，则结果应为：

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

和if OrderID=5

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

顺便说一下，我可以用PHP做到这一点，但我想在一个查询中完成。

Answer 1

这样可以解决问题：

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

在php中将行提取到一个数组中，搜索你的OrderID并获取它之前的那个。

Answer 2

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

另外，如果你有时间看看我的答案会给你一个很好的演示。

Finding free blocks of time in mysql and php?

Answer 3

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

Answer 4

你可以这样做：

(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)

我不确定这个的表现虽然......

Answer 5

这适合我。

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

Answer 6

好的，感谢所有回复，但我得到了自己的回答。

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

MySQL从同一个表中选择当前列和上一列

6 个答案: