Question

我的表格如下所示：

ID   Customer Name   LinkedID
1    A        X      
2    B        Y      1
3    C        Z      2

我需要编写一个查询：

1- For each ID (1,2,3)
2- If there is a LINKEDID defined (2,3 have links)
3- If the CUSTOMER of the LINKEDID is A
4- Return record for that ID

所以在上面的例子中它会做类似的事情：

ID 2,3的指定了LinkedID
ID2链接到＃1，即客户A（好）返回ID2
ID3链接到＃2，即客户B（坏）

所以最终的结果是ID2。

SELECT * FROM TABLE WHERE LINKED <> NULL    // this will get me the list
? But now how do I iterate over each of the results and compare the customers?

非常感谢任何帮助。谢谢，

Answer 1

select t1.id
from your_table t1
inner join your_table t2 on t1.linkedid = t2.id
where t2.customer = 'A'

Answer 2

两次加入桌面。 C是主表，P表示由linkedID引用的父表。

SELECT  *
FROM    CustomerTable C
JOIN    CustomerTable P ON P.ID = C.LinkedID
WHERE   P.Customer = 'A'

SQL Query在单个表中查找链接记录

2 个答案: