Oracle多表�q�接与子查询

Thu, 02 Jul 2009 05:17:00 GMT

1�Q�等��D��?br />      �q�卡��集�q�接
                  select ename, a.deptno as a_deptno,b.deptno as b_deptno ,b.dname as 部门
                  from emp a, dept b

     �{��D��?br />                   select ename, a.deptno as a_deptno,b.deptno as b_deptno ,b.dname as 部门
                  from emp a, dept b
                  where a.deptno = b.deptno;

2�Q�非�{��D��接，在emp表和salgrade表中查找员工的姓名，工资�Q�等�U�，工资上线�Q�工资下�U?br />                  select ename as 姓名, sal as 工资, grade as 工资�{��,losal as 工资上线�Q�hisal as 工资下线
                 from emp, salgrade
                 where sal between losal and hisal;

3:外连
       叛_��q?br />                  select e.ename, d.dname, e.deptno
                 from emp e,dept d
                 where e.deptno = d.deptno(+);

        左外�q�与叛_��q�相�?br />

     以hr登陆查询表employees 和departments �?br />                  select first_name as 姓名, department_name as 部门名称, d.department_id as 部门�~�号
                 from employees e, departments d
                 where e.department_id= d.department_id(+) ;

4:自连�Q�在同一个表中查询每个员工及上司的工号和姓名
                 select a.empno as 员工�~�号, a.ename as 员工姓名, a.mgr as 上司的员工编�? b.ename as 上司姓名
                  from emp a, emp b
                 where a.mgr = b.empno;

5�Q�sql99
交叉�q�接 cross join------相当于��_卡尔�?br /> select e.ename,d.dname
from emp e cross join dept d;

自然�q�接 natural join------相当�{��D��?br /> select e.ename, d.dname
from emp e natural join dept d;

         using子句-----使用同名列查�?br />               select e.ename, d.dname
              from emp e join dept d
              using (deptno);

         on子句 ------当列名不同时用on子句
              用on查询两张�?br />                    select e.ename, d.dname
                    from emp e join dept d
                   on e.deptno = d.deptno;

      用on查询多张�?br />                select e.ename, d.dname
               from emp e join dept d
               on e.deptno = d.deptno
               join �W�三个表
               on �? = �?;

内连接（Inner join�Q?------内连接只�q�回满��q�接条�g的数�?br /> select employee_id, last_name, salary, department_id, department_name
from employees inner join departments using(department_id);

     左外�q?br />               select employee_id, last_name, salary, department_id, department_name
              from employees left join departments using(department_id);

     叛_��q?br />               select employee_id, last_name, salary, department_id, department_name
              from employees right join departments using(department_id);

满外�q?br /> select employee_id, last_name, salary, department_id, department_name
from employees full outer join departments using(department_id);

    子查�?-----------
             查找出工资比scott高的�?br />               select ename, sal from emp
              where sal>
              (select sal from emp where ename='SCOTT');

     查找那些人和scott相同职位的�h
              select ename, job from emp
              where job=
               (select job from emp where ename='SCOTT')
               and ename <> 'SCOTT';

     any的用�?nbsp; < any意味着��于最大�?gt; any大于最��?br />               select empno, ename, sal, job
              from emp
              where sal

     all的用�?nbsp;< all�Q�小于所有，卛_��于最��?gt; all�Q�大于所有，卛_��于最�?br />               select empno, ename, sal, job
              from emp
              where sal

仲宏伟（anmo�Q?/a> 2009-07-02 13:17 发表评论

Thu, 02 Jul 2009 05:15:00 GMT

语法�Q?br />          merge into table_name talbe_alias       //目标�?br />          using(table | view | sub_query) alias      //源表
         on(join condition)                                //合�ƈ数据的条�?br />          when matched then                            //如果条�g成立则更�?br />          update set col1=col_val, col2=co2_val...
         when not matched then                       //如果条�g不成立则插入
         insert (column_list) values(column_values);

�C�Z��Q?br />          //新徏一张表
         create table test1(
          eid number(10),
          name varchar2(20),
          birth date,
          salary number(8,2)
         );

//向表中插入数�?br /> insert into test1 values(1001,'张三','20-5�?,2300);
insert into test1 values(1002,'张三','01-6�?,3000);

//查询表中的数�?br /> select * from test1;

         //新徏�W�二张表�Q�在表中不插入�Q何数�?br />           create table test2(
          eid number(10),
          name varchar2(20),
          birth date,
          salary number(8,2)
         );

         //查询�W�二张表中的数据
         select * from test2;

         //使用merge�q�行数据合�ƈ
         merge into test2
         using test1
         on(test.eid = test2.eid)
         when matched then
          update set name = test1.name, birth = test1.birth, salary = test1.salary
         when not matched then
          insert(eid,name,birth,salary) values(test1.eid, test1.name, test1.birth, test1.salaru);

select * from test2

仲宏伟（anmo�Q?/a> 2009-07-02 13:15 发表评论

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Oracle多表�q�接与子查询