联合查询：
1.等值连接:（内连接，自然连接）
SQL> select d.deptno, d.dname, e.empno, e.ename, e.sal
2 from dept d, emp e
3 where d.deptno=e.deptno;
13 rows selected.
2.非等值连接:
SQL> select e.ename, e.sal, s.grade
2 from emp e, salgrade s
3* where e.sal between s.losal and s.hisal
3.自连接:
SQL> select e.ename, m.ename
2 from emp e, emp m
3 where e.mgr=m.empno;
4.外连接:
sql99(sql2003) standard:
SQL> select e.empno, e.ename, d.dname
2 from emp e left outer join dept d
3 on e.deptno = d.deptno;
14 rows selected.
oracle standard:
SQL> select e.empno, e.ename, d.dname
2 from emp e, dept d
3 where e.deptno=d.deptno(+);
14 rows selected.
oracle can't but sql99 can:
SQL> select e.empno, e.ename, d.dname
2 from emp e full outer join dept d
3 on e.deptno=d.deptno;
15 rows selected.
5.笛卡尔乘积：
SQL> select d.deptno, d.dname, e.empno, e.ename, e.sal
2 from dept d, emp e
56 rows selected.(14 * 4)
子查询:
SQL> select empno, ename, sal
2 from emp
3 where sal > (select sal
4 from emp
5 where ename='BLAKE');
null值处理：
SQL> select empno, ename, sal
2 from emp
3 where empno not in (select mgr
4 from emp);
no rows selected. (And results to now result).
SQL> select empno, ename, sal
2 from emp
3 where empno in (select mgr
4 from emp);
EMPNO ENAME SAL
----- ------ -----
7566 JONES 2975
7698 BLAKE 2850
7782 CLARK 2450
7788 SCOTT 3000
7839 KING 5000
7902 FORD 3000
6 rows selected. (Or results to records).
SQL> select empno, ename, sal
2 from emp
3* where empno not in (select mgr
from emp
where mgr is not null)
EMPNO ENAME SAL
----- ------ -----
7369 SMITH 800
7499 ALLEN 1600
7521 WARD 1250
7654 MARTIN 1250
7844 TURNER 1500
7876 ADAMS 1100
7900 JAMES 950
7934 MILLER 1300
8 rows selected. (Remove null value results to records).
Top N分析：
SQL> select * from (select empno, ename, sal from emp order by sal desc) where rownum < 4 order by rownum;
EMPNO ENAME SAL
----- ------ -----
7839 KING 5000
7788 SCOTT 3000
7902 FORD 3000
Union/Union All/Intersect/Minus：
SQL> break on deptno skip 1;
SQL> select deptno, job, sum(sal)
2 from emp
3 group by deptno, job
4 union
5 select deptno, to_char(null), sum(sal)
6 from emp
7 group by deptno
8 union
9 select to_number(null), to_char(null), sum(sal)
10 from emp;
SQL> select deptno, job, sum(sal) tsal
2 from emp
3 group by rollup(deptno,job);
Insert/Update:
SQL> create table test as
2 select empno, ename, sal
3 from emp
4 where 1=2;
SQL> insert into test values(100, 'tom', null);
SQL> insert into test(empno, ename) values (101, 'mike');
SQL> truncate table test;
SQL> insert into test select empno, ename, sal from emp;
14 rows created.
SQL> show feedback;
FEEDBACK ON for 6 or more rows
SQL> set feedback off;
SQL> set feedback on;
SQL> set feedback 6;
SQL> update test set sal = (select sal from emp where empno=7499) where empno=7369;
Truncate/Delete:
DML(Insert, Update, Delete, Merge)
DDL(Create, Alter, Drop, Rename, Truncate, Comment)
DCL(Grant, Revoke)
Transaction Control(Commit, Rollback, Savepoint)
显示提交：rollback, commit
隐式提交：DDL/DCL,正常退出
begin
commit;
DDL/DCL;
commit;
end
隐式回滚：异常退出
SQL> savepoint A;
Savepoint created.
SQL> delete from test where empno=7369;
1 row deleted.
SQL> rollback to savepoint A;
Create Table, View, Sequence, Index, Synonyms(同义词)
varchar2(10)/varchar2(10 char)
number/number(8, 2)
CLOB(text)/BLOB(Binary, media, exe)
BFile: Binary data stored in an external file
Constraint:
not null, unique, primary key, foreign key,check
SQL> purge recyclebin;
SQL> drop table test purge;
Table:
SQL> create table test(id number, name varchar2(10), create_date date default sysdate);
SQL> insert into test values(100, 'mike', default);
SQL> create table et(eno number,
2 ename varchar2(10),
3 constraint en_u_eno unique(eno));
SQL> create table dt(dno number(4) primary key,
2 dname varchar2(10));
SQL> create table d as select deptno dno, dname, loc from dept;
SQL> create table e as select empno, ename, sal, deptno as dno from emp;
SQL> alter table d add constraint d_pk primary key (dno);
SQL> alter table e add constraint e_fk foreign key (dno) references d(dno);
SQL> drop table e purge;
SQL> create table e(eno number,
2 ename varchar2(10),
3 dno number references d(dno) on delete set null);
SQL> create table e1(eno number,
2 ename varchar2(10),
3 dno number references d(dno) on delete cascade);
SQL> alter table e1 read only;
SQL> create table e2 as select * from emp;
SQL> alter table e2 add constraint ck_e2 check ((sal > 0) and (sal < 10000));
View:
SQL> conn / as sysdba;
SQL> grant create view to scott;
SQL> conn scott/tiger;
SQL> create or replace view v1 as select empno, ename, sal from emp with check option;
SQL> create or replace view v2 as select empno, ename, sal from emp with read only;
Index:
{TODO:}
Sequence:
{TODO:}
Synonym:
SQL> conn / as sysdba;
SQL> grant create synonym to scott;
SQL> conn scott/tiger;
SQL> create synonym sg for salgrade;
