PL\SQL学习笔记(四) 判断与循环

1 判断语句 if

declare
   v_sal emp.sal%type;
begin
    select sal into v_sal from emp
            where empno= 7369;
    if(v_sal < 1200) then
         dbms_output.put_line ('low');
     elsif(v_sal < 2000)then
         dbms_output.put_line ('middle');
     else
         dbms_output.put_line ('high');
     end if;
     end;
/

2 --循环 loop

1)"do-while"

declare
 i binary_integer:=1;
begin
  loop
  dbms_output.put_line(i);
  i:=i+1;
   exit when (i>=11);
end loop;
end;
/

2)" while"

declare
 j binary_integer :=1;
begin
   while j<11 loop
     dbms_output.put_line(j);
         j:=j+1;
end loop;
end;
/

3) "for"

begin
for k in  1..10 loop
    dbms_output.put_line (k);
  end loop;
for k in reverse 1..10 loop
    dbms_output.put_line (k);
  end loop;
end;
/