关键是如何匹配,比如要AAA字段唯一,BBB可不唯一: SQL> select * from test; AAA BBB ---------- -------------------- 1 a 2 b 3 b 1 d 4 b 1 b已选择6行。SQL> select aaa,bbb from ( 2 select aaa,bbb,row_number() over(partition by aaa order by aaa) rn 3 from test) 4 where rn=1; AAA BBB ---------- -------------------- 1 a 2 b 3 b 4 b
与AAA=1匹配的BBB字段就有a、b、d这三个值。选哪个与它匹配呢?
to: vc555 select aaa,bbb from ( 2 select aaa,bbb,row_number() over(partition by aaa order by aaa) rn 3 from test) 4 where rn=1; AAA BBB ---------- -------------------- 1 a 2 b 3 b 4 b高 oracle 怎么这么多东西 select aaa,bbb,row_number() over(partition by aaa order by aaa)
SQL> select * from test; AAA BBB
---------- --------------------
1 a
2 b
3 b
1 d
4 b
1 b已选择6行。SQL> select aaa,bbb from (
2 select aaa,bbb,row_number() over(partition by aaa order by aaa) rn
3 from test)
4 where rn=1; AAA BBB
---------- --------------------
1 a
2 b
3 b
4 b
select aaa,bbb from (
2 select aaa,bbb,row_number() over(partition by aaa order by aaa) rn
3 from test)
4 where rn=1; AAA BBB
---------- --------------------
1 a
2 b
3 b
4 b高 oracle 怎么这么多东西 select aaa,bbb,row_number() over(partition by aaa order by aaa)