delete t1
from t_RMID_RmStkOutItem t1 left join t_RMID_RmStkOutMst t2 on t1.fRmStkOutNo=t2.fRmStkOutNo
where t2.fRmStkOutNo is null
go
left join不是把左边的全部查出来吗？ 但是后面的条件又是表2中的空字符的条件？怎么理解？

你不是有个where条件吗,你那语句的功能和not in等价

[此贴子已经被作者于2007-3-20 11:11:20编辑过]

删除t1中 fRmStkOutNo 字段在t2中是空值的吗？是这样理解？棉花糖麻烦说清楚点？用 not in应该怎么写？

delete t1
from t_RMID_RmStkOutItem t1 left join t_RMID_RmStkOutMst t2 on t1.fRmStkOutNo=t2.fRmStkOutNo
where t2.fRmStkOutNo is null

delete from t_t_RMID_RmStkOutItem where t1.fRmStkOutNo not in (select fRmStkOutNo
from t_RMID_RmStkOutMst) 这两个是等价的