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我在 MySQL 服务器上有两个表：T1 和 T2。ID 是 T1 的主键，ID 是 T2 的外键。

我的问题是：如果我知道与它们相关的 ID（值）但只有在 T1 中找不到该 ID 的情况下，如何在 T2 中插入一些值（使用单个查询）？

T1
id,c1,c2,c3,many other columns
example id:'fry54632' //yes, it is not numerical if matters

T2
id,cc1,cc2,cc3,few other columns
example id:'fry54632', cc1,cc2,cc3... have nothing in common with c1,c2,c3

myDataSource:
countains id, which is same for T1 and T2 and contains some other data that should be
inserted in T2 but not in T1

我想我应该使用这样的东西，但我不确定：

insert into t2 (col1,col2,col3)
select 'const1','const2','const3'
from t1 where not exists 
(select id from t1 t --...t1, I mean: insert 'const1'...and etc strings in t2 if
--specified ID was not found in t1}
where t.id='someID but not t2.id')
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1 回答 1

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INSERT INTO T1 (ID, Col1, Col2)
SELECT ISNULL(T1.ID,-1), ISNULL(T1.Col1,'Arbatory Value'), ISNULL(T1.Col2,'Arbatory Value')
FROM T2
LEFT OUTER JOIN T1
ON T2.ID = T1.ID
WHERE T1.ID IS NULL
于 2012-10-05T17:16:48.627 回答