mysql - LEFT JOIN - 从左表选择中丢失一行

Question

我在执行以下查询时遇到问题:

SELECT 
IFNULL(t4.ItemID, 
IFNULL(t3.ItemID, IFNULL(t2.ItemID, t1.ItemID))) AS ID, 
IFNULL(t4.ParentItemID, 
IFNULL(t3.ParentItemID, 
IFNULL(t2.ParentItemID, t1.ParentItemID))) as Parent, 
IFNULL(tp4.ItemNo, IFNULL(tp3.ItemNo, IFNULL(tp2.ItemNo, tp1.ItemNo))) AS ItemNo
FROM ItemsParents AS t1
LEFT JOIN ItemsDB AS tP1 
ON t1.ItemID = tP1.ID
LEFT JOIN ItemsParents AS t2 
ON t1.ItemID = t2.ParentItemID
LEFT JOIN ItemsDB AS tP2 
ON t2.ItemID = tP2.ID
LEFT JOIN ItemsParents AS t3 
ON t2.ItemID = t3.ParentItemID
LEFT JOIN ItemsDB AS tP3 
ON t3.ItemID = tP3.ID
LEFT JOIN ItemsParents AS t4 
ON t3.ItemID = t4.ParentItemID
LEFT JOIN ItemsDB AS tP4 
ON t4.ItemID = tP4.ID
WHERE t1.ParentItemID = 
(
SELECT ID 
FROM ItemsDB 
WHERE ItemNoInt = 359
)

此表应从选择的第一部分返回两行(822 和 875)，并从以下 ItemsParents LEFT JOINS 附加更多行。它会附加新行，但原始两行中的一行会丢失。
822
859
834
846
810
...所以第 875 行丢失了。
如果我从父项中删除或禁用 LEFT JOIN(通过 "= 1 -- " - 注释掉原始条件):

SELECT IFNULL
(
t4.ItemID, 
IFNULL(t3.ItemID, IFNULL(t2.ItemID, t1.ItemID))) AS ID, 
IFNULL(t4.ParentItemID, 
IFNULL(t3.ParentItemID, 
IFNULL(t2.ParentItemID, t1.ParentItemID))) as Parent, 
IFNULL(tp4.ItemNo, 
IFNULL(tp3.ItemNo, IFNULL(tp2.ItemNo, tp1.ItemNo))) AS ItemNo
FROM ItemsParents AS t1
LEFT JOIN ItemsDB AS tP1 
ON t1.ItemID = tP1.ID
LEFT JOIN ItemsParents AS t2 
ON t1.ItemID = 1 -- t2.ParentItemID
LEFT JOIN ItemsDB AS tP2 
ON t2.ItemID = tP2.ID
LEFT JOIN ItemsParents AS t3 
ON t2.ItemID = 1 -- t3.ParentItemID
LEFT JOIN ItemsDB AS tP3 
ON t3.ItemID = tP3.ID
LEFT JOIN ItemsParents AS t4   -- t4.ParentItemID
ON t3.ItemID = 1 
LEFT JOIN ItemsDB AS tP4 
ON t4.ItemID = tP4.ID
WHERE t1.ParentItemID = 
(
SELECT ID 
FROM ItemsDB 
WHERE ItemNoInt = 359
)

...我从左连接表(822 和 875)返回正确的两行。

我用谷歌搜索了左连接表中丢失行的案例，但它们似乎都不适用于这种情况。有什么想法吗？

问候，

伦敦银行同业拆借利率

Answer 1

不是答案，只是想法，我希望您已经要求在左连接中查找表的最后一行，

select LastRowofSubTable.* from tableMain
outer apply
(
    select top 1 * from tableSub
    where tableMain.id = tableSub.id
    order by tableSub.pk_id desc
)as LastRowofSubTable