PL/SQL 三个小例子

/*
SQL语句
员工集合：select to_char(hiredate,'yyyy') from emp --> 光标  --> 循环--> 退出条件：notfound

变量
count80 number := 0;
count81 number := 0;
count82 number := 0;
count87 number := 0;
*/
set serveroutput on
declare
cursor cemp is select to_char(hiredate,'yyyy') from emp;
phiredate varchar2(4);
count80 number := 0;
count81 number := 0;
count82 number := 0;
count87 number := 0;
begin
open cemp;
loop
--取一个员工
fetch cemp into phiredate;
exit when cemp%notfound;
--判断年份
if phiredate = '1980' then count80:=count80+1;
elsif phiredate = '1981' then count81:=count81+1;
elsif phiredate = '1982' then count82:=count82+1;
else count87:=count87+1;
end if;

end loop;
close cemp;
--输出
dbms_output.put_line('Total:'||(count80+count81+count82+count87));
dbms_output.put_line('1980:'||count80);
dbms_output.put_line('1981:'||count81);
dbms_output.put_line('1982:'||count82);
dbms_output.put_line('1987:'||count87);
end;
/

/*
SQL语句
员工集合: select empno,sal from emp order by sal
--> 光标 --> 循环 --> 退出条件：1. 总额>5w  2. notfound

变量
涨工资的人数: countEmp number := 0;
涨后工资总额： salTotal number;
1. select sum(sal) into salTotal from emp;
2. 涨后 = 涨前 + sal *0.1

练习:把程序改对
*/
set serveroutput on
declare
cursor cemp is select empno,sal from emp order by sal;
pempno emp.empno%type;
psal   emp.sal%type;

--涨工资的人数:
countEmp number := 0;
--涨后工资总额：
salTotal number;
begin
--得到初始的工资总额
select sum(sal) into salTotal from emp;

open cemp;
loop
--1. 总额>5w
exit when salTotal > 50000;
--取一个员工
fetch cemp into pempno,psal;
--2. notfound
exit when cemp%notfound;

update emp set sal=sal*1.1 where empno=pempno;
--人数加一
countEmp:=countEmp+1;

--涨后 = 涨前 + sal *0.1
salTotal := salTotal + psal*0.1;
end loop;
close cemp;

commit;
dbms_output.put_line('人数:'||countEmp||'   总额:'||salTotal);

end;
/

set serveroutput on
declare
cursor cdept is select deptno from dept;
pdeptno dept.deptno%type;

cursor cemp(dno number) is select sal from emp where deptno=dno;
psal emp.sal%type;
--每个段的人数
count1 number; count2 number; count3 number;
--部门的工资的工资:
saltotal number;
begin
open cdept;
loop
--取一个部门
fetch cdept into pdeptno;
exit when cdept%notfound;

--初始化
count1:=0; count2:=0; count3:=0;
select sum(sal) into saltotal from emp where deptno=pdeptno;

--得到部门中员工的薪水
open cemp(pdeptno);
loop
--取一个员工
fetch cemp into psal;
exit when cemp%notfound;
--判断薪水所在的区间
if psal < 3000 then count1:=count1+1;
elsif psal>=3000 and psal<6000 then count2:=count2+1;
else count3:=count3+1;
end if;
end loop;
close cemp;

--保存当前部门的结果
insert into msg values(pdeptno,count1,count2,count3,nvl(SALTOTAL,0));

end loop;
close cdept;
commit;
end;
/