oracle查询去除数据重复

单个字段
select * from ZTEMP_DRUG_ATC where atc_code in(select atc_code from ZTEMP_DRUG_ATC group by atc_code having count(atc_code) >1)

DELETE  ZTEMP_DRUG_ATC WHERE (atc_code) IN ( SELECT atc_code FROM ZTEMP_DRUG_ATC GROUP BY atc_code HAVING COUNT(atc_code) > 1) 
AND ROWID NOT IN (SELECT MIN(ROWID) FROM ZTEMP_DRUG_ATC GROUP BY atc_code HAVING COUNT(*) > 1);