[英]Having trouble self joining a table with NULL values
需要使用 LEFT 连接,因此即使右表中没有匹配项,也会返回每一行
SELECT A.[name] AS Child
,B.[name] AS Parent1
,C.[name] AS Parent2
FROM YourTable AS A
LEFT JOIN YourTable AS B
ON A.ParentID1 = B.PersonID
LEFT JOIN YourTable AS C
ON A.ParentID2 = C.PersonID
WHERE A.ParentID1 IS NOT NULL
OR A.ParentID2 IS NOT NULL
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