sql语句删除重复的记录的方法
例如：

SQL>delete from employee e2 where rowid not in (        select max(e1.rowid) from employee e1 where        e1.emp_id=e2.emp_id and e1.emp_name=e2.emp_name and e1.salary=e2.salary);--这里用min(rowid)也可以。 SQL>delete from employee e2 where rowid <(        select max(e1.rowid) from employee e1 where        e1.emp_id=e2.emp_id and e1.emp_name=e2.emp_name and                  e1.salary=e2.salary);（3）也是通过rowid，但效率更高。 SQL>delete from employee where rowid not in (        select max(t1.rowid) from employee t1 group by         t1.emp_id,t1.emp_name,t1.salary);--这里用min(rowid)也可以。      EMP_ID EMP_NAME                                     SALARY---------- ---------------------------------------- ----------         1 sunshine                                      10000         3 xyz                                             30000         2 semon                                         20000