【PL/SQL练习】基本的PL/SQL语句

1.无变量匿名快

begin
  dbms_output.put_line('Hello World');
  end;

2.有变量的匿名块，定义变量：

declare
 v_ename varchar2(10);
  v_sal number(7,2);
begin
 select ename,sal into v_ename,v_sal from emp where empno=&n;
  dbms_output.put_line('Employee name is: '||v_ename);
  dbms_output.put_line('Employee sal is: '||v_sal);
  end;

3.定义常量和变量并赋值：

declare
v_ename VARCHAR2(10);
v_sal   NUMBER(7,2);
c_empno constant  NUMBER(4):=7788;               //声明一个常量

begin
  
 select ename,sal into v_ename,v_sal from emp where empno=c_empno;
  
dbms_output.put_line('Employees name is: '||v_ename)；
dbms_output.put_line('Employees salary is: '||v_sal); 

end;

4.在执行部分给变量赋值：

declare
v_ename varchar2(10);
v_sal number(7,2);
v_empno number(4);
begin
  v_empno :=7788;
  select ename,sal into v_ename,v_sal from emp where empno=v_empno;
  dbms_output.put_line('Employee name is: '||v_ename);
  dbms_output.put_line('Employee sal is: '||v_sal);
  end;

5.异常处理：

declare
v_ename varchar2(10);
v_sal number(7,2);
begin
  select ename,sal into v_ename,v_sal from emp where empno=&n;
  dbms_output.put_line('Employee name is: '||v_ename);
  dbms_output.put_line('Employee sal is: '||v_sal);
  exception
    when no_data_found then
      dbms_output.put_line('Please input current number!');
  end;

6.通过%type，保证变量的数据类型和表中字段的数据类型一致：

declare
v_ename emp.ename%type;
v_sal emp.sal%type;
begin 
  select ename,sal into v_ename,v_sal from emp where empno=&n;
  dbms_output.put_line('Employee name is: '||v_ename);
  dbms_output.put_line('Employee sal is: '||v_sal);
  exception
    when no_data_found then
      dbms_output.put_line('Please input current number!');
  end;