可以啊
08:33:43 SQL> select * from a; A_ID1 A_ID2 A_NAME
--------- --------- ----------
1 1 A_11
2 1 A_21
3 1 A_31实际:591
09:11:45 SQL> select distinct a_id2 from a; A_ID2
---------
1实际:711
09:11:56 SQL> select distinct a_id1,a_id2 from a; A_ID1 A_ID2
--------- ---------
1 1
2 1
3 1实际:80
09:12:08 SQL>
08:33:43 SQL> select * from a; A_ID1 A_ID2 A_NAME
--------- --------- ----------
1 1 A_11
2 1 A_21
3 1 A_31实际:591
09:11:45 SQL> select distinct a_id2 from a; A_ID2
---------
1实际:711
09:11:56 SQL> select distinct a_id1,a_id2 from a; A_ID1 A_ID2
--------- ---------
1 1
2 1
3 1实际:80
09:12:08 SQL>
select distinct a,b,c,d from test
select distinct a,b,c,d from test
那如果还有个E字段我不想压缩但也要显示,怎么做.
FROM prodq,rpt_emp,
(Select min(prod_pri) MIN_VAL,mfg_no,Sec_no From Sprice Group By mfg_no,sec_no ) MINPRI
Where ((prodq.mfg_no=minpri.mfg_no) and (prodq.sec_no=minpri.sec_no))
Group by prodq.prod_date,prodq.fac_no,prodq.emp_no
这个prodq里有大概40多万笔资料,没加Group By以前大概3秒钟资料就出来了,加了Group By后,大概要6,7分钟,郁闷啊,怎么回事