关于 not in

[yaotiebing]

select usercode from table1 where usercode not in (select Usercode from table2) 这样的sQL 语句执行起来的效率非常低 有没有好的实现方法

[yaotiebing]

minus 比 not in 的效率高吗？？

[enhydraboy]

select table1.usercode from table1,table2 where
table1.usercode = table2.usercode(+) and table2.username is null

[hdkkk]

select usercode from table1 where usercode not exists (select Usercode from table2)

select t1.usercode from table1 t1,table2 t2 where t1.usercode<>t2.usercode

[armu80830]

select usercode from table1
minus
select Usercode from table2

[jiezhi]

select a.usercode from table1 a,table2 b where
a.usercode<>b.usercode

[hdkkk]

我的错了,请勿略

[hh23_]

select t1.usercode from table1 t1,table2 t2 where t1.usercode<>t2.usercode

[hdkkk]

select usercode from table1 minus (select Usercode from table2)

[hdkkk]

select usercode from t1 where not exists (select 'X' from t2 where t1.usercode=t2.usercode)