测试一下不就清楚了吗 SQL> select * from test1; COLID COLTEST ---------- -------------------- 1 aa 2 bb 3 cc 5 ddSQL> select * from test2; COLID COLNAME ---------- -------------------- 1 aa test 3 cc test 4 dd test SQL> select test1.colid,test1.coltest,test2.colname 2 from test1,test2 3 where test1.colid(+)=test2.colid; COLID COLTEST COLNAME ---------- -------------------- -------------------- 1 aa aa test 3 cc cc test dd testSQL> select test1.colid,test1.coltest,test2.colname 2 from test1,test2 3 where test1.colid=test2.colid(+); COLID COLTEST COLNAME ---------- -------------------- -------------------- 1 aa aa test 2 bb 3 cc cc test 5 dd
SQL> select * from test1; COLID COLTEST
---------- --------------------
1 aa
2 bb
3 cc
5 ddSQL> select * from test2; COLID COLNAME
---------- --------------------
1 aa test
3 cc test
4 dd test
SQL> select test1.colid,test1.coltest,test2.colname
2 from test1,test2
3 where test1.colid(+)=test2.colid; COLID COLTEST COLNAME
---------- -------------------- --------------------
1 aa aa test
3 cc cc test
dd testSQL> select test1.colid,test1.coltest,test2.colname
2 from test1,test2
3 where test1.colid=test2.colid(+); COLID COLTEST COLNAME
---------- -------------------- --------------------
1 aa aa test
2 bb
3 cc cc test
5 dd