经典的左连接/ isnull测试
select A.*
from secondTbl A
left join firstTbl B on A.guid = B.guid
WHERE B.guid is null
从两个表中查找不匹配ID的最快方法
经典的左连接/ isnull测试
select A.*
from secondTbl A
left join firstTbl B on A.guid = B.guid
WHERE B.guid is null