I用户INNER JOIN,但它似乎并不高效:
DELETE from table1
FROM table1 as a INNER JOIN table2 as b
ON b.pk1=a.pk1
AND b.pk2=a.pk2
MERGE的声明基本相同:
MERGE table1 AS target
USING table2 AS source
ON (target.pk1= source.pk1 AND target.pk2=source.pk2)
WHEN MATCHED
THEN DELETE;
有更好的方法吗?谢谢
事实上,merge语句在后台执行内部联接,就像delete语句一样。在这种情况下,没有具体的方法来提高性能。然而,应用分发类型、分区和索引的适当组合可以提高内部联接性能。