Oracle循环语句

Posted 2020-09-30 loyer

select * from goods;
       a char(10):=‘三星‘   --定长字符串
       b varchar2(10):=‘三星‘;    --可变字符串
       c binary_integer:=‘10001‘;        --带符号整数,为整数计算优化性能 
       d number(5,2):=‘123.45‘;           --数值
       e long                   --变长字符串 
       f date                   --日期
       g boolean                --布尔
       h rowid                  --存放数据库行号 
       i Goods.Gname%type:=‘三星‘;          --用%type定义与表相配的属性类型
------------------------------------------------------if语句
declare 
       c binary_integer:=‘10002‘;
begin 
       if c>10 then update Goods set Gnote=‘\(^o^)/~‘ where Gid=c;
       end if;
end;
------------------------------------------------------if..else语句
declare
       a number(4,2):=‘13.45‘;
       d number(5,2):=‘123.45‘;
begin
       if a>d then DBMS_OUTPUT.put_line(‘AAA‘);
       else DBMS_OUTPUT.put_line(‘BBB‘);
       end if;
end;
------------------------------------------------------if..elsif..else语句
declare
       a varchar2(10):=‘823‘;
       b varchar2(10):=‘12a3456‘;
       c number:=‘132456798‘;
begin
       if a<b and a>c then DBMS_OUTPUT.put_line(‘AAA‘);
       elsif a>b or a>c then DBMS_OUTPUT.put_line(‘BBB‘);   --字符串比较是从下标第一个开始比
       elsif a<c then DBMS_OUTPUT.put_line(‘CCC‘);
       else DBMS_OUTPUT.put_line(‘DDD‘);
       end if;
end;
------------------------------------------------------case语句
declare
       a char(10):= upper(‘&p_grade‘);
       b varchar2(10);       
begin 
       b:= case a
       when ‘A‘ then ‘123‘
       when ‘B‘ then ‘456‘
       when ‘C‘ then ‘789‘
       else ‘NO‘
       end;
       DBMS_OUTPUT.put_line(b||‘ABCD‘);
end;
------------------------------------------------------loop循环
declare
        a number(10):=0;
begin
        loop a:=a+1;
        DBMS_OUTPUT.put_line(‘a的当前值为‘||a);
        exit when a=10;
        end loop;
end;
------------------------------------------------------for循环
declare
        a char(10):=1;              
begin
        for x in 1..10 loop 
        DBMS_OUTPUT.put_line(‘a的当前值为‘||a);
        end loop;
end;
------------------------------------------------------for循环使用关键字reverse(倒序循环)
declare
        a varchar2(10):=10;
begin
        for a in reverse 1..10 loop
        DBMS_OUTPUT.put_line(‘a的当前值为‘||a);
        end loop;
end;  
------------------------------------------------------while循环
declare
        a number:=1;
begin
        while a<=10 loop
        DBMS_OUTPUT.put_line(‘a的当前值为‘||a);
        a:=a+1;
        end loop;
end;  
------------------------------------------------------用for循环添加属性
create table Demo (DID number(5),Dname varchar2(10));
select * from Demo;
declare
       a number:=1;
       b varchar2(10):=‘Jack‘;
begin
       for a in 1..10 loop
       insert into Demo(DID,DNAME) values (a,b);
       end loop;
       for a in 1..10 loop
       insert into Demo(DNAME) values (b);
       end loop;
end;
delete from Demo
------------------------------------------------------
declare
       a number:=1;
begin
  loop 
  DBMS_OUTPUT.put_line(‘a的当前值为‘||a);
  a:=a+1;
  if a>10
  then goto loyer;
  end if;
  end loop;
  <<loyer>>
  null;     --不需要处理任何数据
  DBMS_OUTPUT.put_line(‘ABCD‘);
end;
------------------------------------------------------