从一个表中删除哪里的色彩不在另一个表中

Question

我想从表中删除他们不存在于另一个表中的清单。 我能够与选择列表：

SELECT count(mlsnum) as oldRecords 
FROM coordinates 
WHERE mlsnum NOT IN 
(SELECT mlsnum 
FROM RETS_Listings_full) 

但是当我尝试删除清单，我不能

delete FROM coordinates t1 
LEFT JOIN RETS_Listings_full t2 
ON t2.MLSNUM = t1.MLSNUM 
WHERE t2.mlsnum IS NULL 

错误说 - 消息102，级别15，状态1 ，第1行 't1'附近语法不正确。

Answer 1

可以检索mlsnum列表，并删除这种方式

DELETE FROM coordinates 
WHERE mlsnum IN (
    SELECT mlsnum 
    FROM coordinates 
    WHERE mlsnum NOT IN (
    SELECT mlsnum 
    FROM RETS_Listings_full) 
) 

Answer 2

delete from mytable where somecommonid not in(select id from myothertable) 

Answer 3

...他们不存在...

你说的很接近解决方案：使用NOT EXISTS：

DELETE FROM coordinates t1 
WHERE NOT EXISTS 
(
    SELECT 1 FROM RETS_Listings_full t2 
    WHERE t1.mlsnum = t2.mlsnum 
) 

Answer 4

你的第二个查询

DELETE t1 
FROM coordinates t1 LEFT JOIN RETS_Listings_full t2 ON t2.MLSNUM = t1.MLSNUM 
WHERE t2.mlsnum IS NULL