Mega Code Archive
Select from a Subquery
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SQL>
SQL> create table history
2 ( empno NUMBER(4)
3 , beginyear NUMBER(4)
4 , begindate DATE
5 , enddate DATE
6 , deptno NUMBER(2)
7 , msal NUMBER(6,2)
8 , comments VARCHAR2(60)
9 ) ;
Table created.
SQL>
SQL> insert into history values (9,2000,date '2000-01-01',date '2002-01-02',40, 950,'history for 9');
1 row created.
SQL> insert into history values (8,2000,date '2000-01-02', NULL ,20, 800,'');
1 row created.
SQL> insert into history values (7,1988,date '2000-01-06',date '2002-01-07',30,1000,'');
1 row created.
SQL> insert into history values (6,1989,date '2000-01-07',date '2002-01-12',30,1300,'');
1 row created.
SQL> insert into history values (5,1993,date '2000-01-12',date '2002-01-10',30,1500,'history for 5');
1 row created.
SQL> insert into history values (4,1995,date '2000-01-10',date '2002-01-11',30,1700,'');
1 row created.
SQL> insert into history values (3,1999,date '2000-01-11', NULL ,30,1600,'');
1 row created.
SQL> insert into history values (2,1986,date '2000-01-10',date '2002-01-08',20,1000,'history for 2');
1 row created.
SQL> insert into history values (1,1987,date '2000-01-08',date '2002-01-01',30,1000,'history for 1');
1 row created.
SQL> insert into history values (7,1989,date '2000-01-01',date '2002-05-12',30,1150,'history for 7');
1 row created.
SQL>
SQL> select *
2 from (select empno, msal
3 from history
4 order by msal desc)
5 where rownum <= 3;
EMPNO MSAL
------ ------
4 1700
3 1600
5 1500
3 rows selected.
SQL>
SQL> drop table history;
Table dropped.
SQL>
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