12-4 plsql中使用循环语句
练习使用plsql输出7369的姓名，工作，工资及雇佣日期
declare
v_emp emp%rowtype;
begin
select * into v_emp from emp where empno=7369;
dbms_output.put_line(v_emp.ename||' '||v_emp.job||' '||v_emp.sal||' '||v_emp.hiredate);
end;
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根据用户的编号输出该用户的姓名，工作，工资及雇佣日期
declare
v_emp emp%rowtype;
begin
select * into v_emp from emp where empno=&bianhao;
dbms_output.put_line(v_emp.empno||'的：'||v_emp.ename||' '||v_emp.job||' '||v_emp.sal||' '||v_emp.hiredate);
end;
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取出7369的薪水，如果小于1200则输出“low”,如果小于2000,则输出middle,否则输出high
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;
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取出用户输入编号的薪水，如果小于1200则输出“low”,如果小于2000,则输出middle,否则输出high
declare
v_sal emp.sal%type;
begin
select sal into v_sal from emp where empno=&bianhao;
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;
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2.若用户编号不存在怎么办?
declare
v_sal emp.sal%type;
begin
select sal into v_sal from emp where empno=&bianhao;
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;
exception
when others then
dbms_output.put_line('异常');
end;
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判断7839的薪水，如果小于2500就将其工资减半，如果高于2500就将其工资减半，如果等于2500就将其工资输出
declare
v_sal emp.sal%type;
begin
select sal into v_sal from emp where empno=7839;
if v_sal<2500 then
update emp set sal=v_sal*2 where empno=7839;
elsif v_sal>2500 then
update emp set sal=v_sal/2 where empno=7839;
else
dbms_output.put_line(v_sal);
end if;
end;
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循环结构
1)直到型循环
loop
...
exit...
ens loop
输出1-10
declare
i binary_integer:=1;
begin
loop
dbms_output.put_line(i);
i:=i+1;
exit when (i=11); --等号为比较符
end loop;
end;
/
2)while loop循环
while条件 loop
...
end loop;
declare
i binary_integer:=1;
begin
while(i<11) loop
dbms_output.put_line(i);
i:=i+1;
end loop;
end;
3)计数型循环
输出1-10 和10-1
declare
i binary_integer:=1;
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;