Oracle游标总结三

-- 声明游标；CURSOR cursor_name IS select_statement
 
--For 循环游标
--（1）定义游标
--（2）定义游标变量
--（3）使用for循环来使用这个游标,for循环时

declare
  cursor c_job
  is
  select empno,ename,job,sal from emp
  where job='MANAGER';
  c_row c_job%rowtype;
begin
  open c_job;
    for c_row in c_job loop
        dbms_output.put_line(c_row.empno||c_row.ename)
    end loop;
  close c_job;
end

--Fetch游标
--使用的时候必须要明确的打开和关闭

declare
  cursor c_job
  is
  select empno,ename from emp
  where job='MANAGER';
  c_row c_job%rowtype;
begin
  open c_job;
     loop
       fetch c_job into c_row;
       --判读是否提取到值，没取到值就退出
       --取到值c_job%notfound 是false
       --取不到值c_job%notfound 是true
       exit when c_job%notfound;
      end loop
   close c_job;
end;

--1：任意执行一个update操作，用隐式游标sql的属性%found,%notfound,%rowcount,%isopen观察update语句的执行情况。

begin
    update emp set ENAME='ALEARK' WHERE EMPNO=7469;
    if sql%isopen then
        dbms_output.put_line('Openging');
    else
        dbms_output.put_line('closing');
    end if;
    if sql%found then
        dbms_output.put_line('游标指向了有效行');--判断游标是否指向有效行
    else
        dbms_output.put_line('Sorry');
    end if;
    if sql%notfound then
        dbms_output.put_line('Also Sorry');
    else
        dbms_output.put_line('Haha');
    end if;
        dbms_output.put_line(sql%rowcount);
    exception
    when no_data_found then
        dbms_output.put_line('Sorry No data');
    when too_many_rows then
        dbms_output.put_line('Too Many rows');
end;

declare
    empNumber emp.EMPNO%TYPE;
    empName emp.ENAME%TYPE;
begin
    if sql%isopen then
        dbms_output.put_line('Cursor is opinging');
    else
        dbms_output.put_line('Cursor is Close');
    end if;
    if sql%notfound then
        dbms_output.put_line('No Value');
    else
        dbms_output.put_line(empNumber);
    end if;
        dbms_output.put_line(sql%rowcount);
        dbms_output.put_line('-------------');
 
        select EMPNO,ENAME into  empNumber,empName from emp where EMPNO=7499;
        dbms_output.put_line(sql%rowcount);
 
    if sql%isopen then
        dbms_output.put_line('Cursor is opinging');
    else
        dbms_output.put_line('Cursor is Closing');
    end if;
    if sql%notfound then
        dbms_output.put_line('No Value');
    else
        dbms_output.put_line(empNumber);
    end if;
    exception
    when no_data_found then
        dbms_output.put_line('No Value');
    when too_many_rows then
        dbms_output.put_line('too many rows');
end;

--2,使用游标和loop循环来显示所有部门的名称
--游标声明

declare
   cursor csr_dept
   is
   select dname from depth;
   row_dept csr_dept%rowtype;
begin
   for row_dept in csr_dept loop
       dbms_output.put_line(row_dept.dname);
   end loop;
end;

--3,使用游标和while循环来显示所有部门的的地理位置（用%found属性）

declare
   cursor csr_TestWhile
   is
   select LOC from Depth;
   row_loc csr_TestWhile%rowtype;
begin
   open csr_TestWhile;
   --必须先fetch一遍,才能进行%found判断,否则一直都是空为false
   fetch csr_TestWhle into row_loc;
     while csr_TestWhile%found loop
       dbms_output.put_line(row_loc.LOC);
       fetch csr_TestWhile into row_loc;
     end loop;
     close csr_TestWhile;
end

--4,接收用户输入的部门编号，用for循环和游标，打印出此部门的所有雇员的所有信息(使用循环游标)
--CURSOR cursor_name[(parameter[,parameter],...)] IS select_statement;
--定义参数的语法如下:Parameter_name [IN] data_type[{:=|DEFAULT} value]  

declare
 --定义带参数的游标
 cursor c_dept(p_deptNo number)
 is
 select * from emp where emp.depno=p_deptNo;
 r_emp emp%rowtype;
begin
  --遍历游标,调用游标传参数
  for r_emp in c_dept(20) loop
    dbms_output.put_line('员工号：'||r_emp.EMPNO||'员工名：'||r_emp.ENAME||'工资：'||r_emp.SAL);
  end loop;
end;

--6：用更新游标来为雇员加佣金：(用if实现,创建一个与emp表一摸一样的emp1表，对emp1表进行修改操作),并将更新前后的数据输出出来 

       create table emp1 as select * from emp;
 
declare
        cursor
        csr_Update
        is
        select * from  emp1 for update OF SAL;
        empInfo csr_Update%rowtype;
        saleInfo  emp1.SAL%TYPE;
begin
    FOR empInfo IN csr_Update LOOP
      IF empInfo.SAL<1500 THEN
        saleInfo:=empInfo.SAL*1.2;
       elsif empInfo.SAL<2000 THEN
        saleInfo:=empInfo.SAL*1.5;
        elsif empInfo.SAL<3000 THEN
        saleInfo:=empInfo.SAL*2;
      END IF;
      UPDATE emp1 SET SAL=saleInfo WHERE CURRENT OF csr_Update;
     END LOOP;
END;

--7:编写一个PL/SQL程序块，对名字以‘A’或‘S’开始的所有雇员按他们的基本薪水(sal)的10%给他们加薪(对emp1表进行修改操作)

declare
   cursor csr_addSal
   is select sal from emp where ename like 'A%' or ename like'S%';
   r_addSal csr_addSal%rowtype;
   saleInfo emp.sal%type;
begin
  for r_addSal in csr_addSal loop
      saleInfo := r_addSal.sal*1.1;
      update emp set sal = saleInfo where ename like 'A%' or ename like'S%';
  end loop;
end

--8：编写一个PL/SQL程序块，对所有雇员按他们的基本薪水(sal)的20%为他们加薪，
--如果增加的薪水大于300就取消加薪(对emp1表进行修改操作，并将更新前后的数据输出出来) 

declare
 cursor
  crs_UpadateSal
  is select sal from emp;
  r_UpadateSal crs_UpadateSal%rowtype
  salAdd emp.sal%type;
  salInfo emp.sal%type;
begin
  for r_UpadateSal in crs_UpadateSal loop
    salAdd:=r_UpadateSal.sal*0.2;
    if salAdd>300 then
       salInfo:=r_r_UpadateSal.sal;
    else
       salInfo:=r_UpadateSal.sal+salAdd;
      end if
     update emp set sal=salInfo where current of crs_UpadateSal;
    end loop;
end;

--9:将每位员工工作了多少年零多少月零多少天输出出来   
--近似
  --CEIL(n)函数：取大于等于数值n的最小整数
  --FLOOR(n)函数：取小于等于数值n的最大整数
  --truc的用法 http://publish.it168.com/2005/1028/20051028034101.shtml

declare
    cursor
      crs_workDay
      is select ename,hirdate,trunc(months_between(sysdate,hirdate)/12) as years,
      trunc(mod(months_between(sysdate,hirdate),12)) as monthss,
      trunc(mod(sysdate-hirdate),365),12) as days
      from emp
      r_workDay crs_workDay%rowtype;
begin
  for r_workDay in crs_workDay loop
    dbms_output.put_line(r_WorkDay.ENAME||'已经工作了'||r_WorkDay.SPANDYEARS||'年,零'||r_WorkDay.months||'月,零'||r_WorkDay.days||'天');
    end loop;
end

--10:输入部门编号，按照下列加薪比例执行(用CASE实现，创建一个emp1表，修改emp1表的数据),并将更新前后的数据输出出来
--  deptno  raise(%)
--  10      5%
--  20      10%
--  30      15%
--  40      20%
--  加薪比例以现有的sal为标准
--CASE expr WHEN comparison_expr THEN return_expr
--[, WHEN comparison_expr THEN return_expr]... [ELSE else_expr] END

declare
 cursor
  crs_caseTest
  is select deptNo,sal from emp;
  r_caseTest crs_caseTest%rowtype;
  salInfo emp.sal%rowtype;
begin
  for r_caseTest in crs_caseTest loop
      case
        when r_caseTest.deptNo=10 then
        salInfo = r_caseTest.sal*1.05;
        when r_caseTest.deptNo=10 then
        salInfo = r_caseTest.sal*1.1;
        when r_caseTest.deptNo=10 then
        salInfo = r_caseTest.sal*1.15;
        when r_caseTest.deptNo=10 then
        salInfo = r_caseTest.sal*1.2;
       end case;
       update emp set sal = salInfo where current of crs_caseTest;
  end loop;
end;

--13:对每位员工的薪水进行判断，如果该员工薪水高于其所在部门的平均薪水，则将其薪水减50元，输出更新前后的薪水，员工姓名，所在部门编号。
--AVG([distinct|all] expr) over (analytic_clause)
---作用：
--按照analytic_clause中的规则求分组平均值。
  --分析函数语法:
  --FUNCTION_NAME(<argument>,<argument>...)
  --OVER
  --(<Partition-Clause><Order-by-Clause><Windowing Clause>)
     --PARTITION子句
     --按照表达式分区(就是分组),如果省略了分区子句,则全部的结果集被看作是一个单一的组

DECLARE
 cursor csr_agvSal
 is select empno,sal,avg(sal) over (parition by deptno) as avgSal from emp;
 r_avgSal csr_agvSal%rowtype;
 salInfo emp.sal%type;
begin
  for r_avgSal in csr_agvSal loop
      if r_avgSal.sal>r_avgSal.avgSal then
         salInfo := r_avgSal.sal-50;
        end if;
        update emp set sal = salInfo where current of csr_agvSal;
  end loop;
end;