mysql 根据某个字段去重

1、法一

select a.*, count(distinct a.PROC_NO)from bpm_proc_mstr a left join bpm_proc_log b on a.PROC_ID=b.PROC_ID where 1=1  and a.del_flag!=0  and  a.BU_NO='XMYZ10051' and b.EXEC_PSN =1871 and a.OUT_FLOW_NO='171010001269'GROUP BY a.PROC_NOorder by  CREATE_DATE DESC;

2、法二

select a.*from bpm_proc_mstr a left join bpm_proc_log b on a.PROC_ID=b.PROC_ID where 1=1  and a.del_flag!=0  and  a.BU_NO='XMYZ10051' and b.EXEC_PSN =1871 and a.OUT_FLOW_NO='171010001269'GROUP BY a.PROC_NOorder by  CREATE_DATE DESC;