A3:insert into B(sqluser, sqltitle) values( selct user, title from ( select top 100 user, title from A order by id EXCEPT select top 19 user, title from A order by id ))EXCEPT 似乎要到SQL Server 2005 才支持;而Oracle 9i2有Minus关键字表达同样的意思;其他的数据库不熟悉未经测试