SQL INSERT是否存在删除如果不是2个表

Question

寻找一个SQL查询来执行以下操作之间存在：的table1x列

1. 全部插入值y列table2如果 它们不存在在表2
2. 从table2列的删除记录，如果clumn y的值不会再在 的table1

x列中存在

我试图插入或忽略在SQL Server中，没有运气插入查询2008 R2

Answer 1

听起来像是一个完美的适合SQL Server MERGE;

MERGE table2 AS t2 
USING table1 AS t1 
ON (t2.y = t1.x) 
WHEN NOT MATCHED BY TARGET 
    THEN INSERT (y) VALUES(t1.x) 
WHEN NOT MATCHED BY SOURCE 
    THEN DELETE; 

An SQLfiddle to test with。

Answer 2

这将插入你在表1，COLX，所有记录到表2，科利：

INSERT INTO Table2 (ColY) 
SELECT ColX 
FROM Table1 
WHERE ColX NOT IN (SELECT ColY FROM Table2) 

你可以用” t删除列中的所有记录。但是，你可以将它们设置为NULL，或者如果你想删除这些行，你也可以这样做。请让我们知道。

DELETE FROM Table2 
WHERE ColY NOT IN (SELECT ColX From Table1) 

OR

UPDATE Table2 
SET ColY = NULL 
WHERE ColY NOT IN (SELECT ColX From Table1) 

好运。

Answer 3

可以使用Merge Statement

MERGE table2 AS t2 
USING table1 AS t1 
ON (t2.y = t1.x) 
WHEN NOT MATCHED BY TARGET 
    THEN INSERT(y) VALUES(t1.x) 
WHEN NOT MATCHED BY SOURCE 
    THEN DELETE 
OUTPUT $action, inserted.*, deleted.*;